Hello, I am Andy Zhu, I am a high school student at St. George's School an undergrad at the University of Cambridge interested in Competitive Programming. This repo is just for me to review my own solutions
andy_zhu23 on DMOJ
Wizard_of_Orz on codeforces
Wizard_of_Orz on LeetCode
Wizard_of_Orz on AtCoder
| task | date | time |
|---|
| task | date | time | score | reflection |
|---|---|---|---|---|
| CCC 2023 | Feb 15th | 8:00am | 63 | FINALLY HAD ONE GOOD CCC |
| USACO Jan 2022 Platinum | Jan 30th | 9:00 | 100 | too hard |
| USACO Dec 2022 Platinum | Dec 19th | 9:00 | 550(90th) | Solved 1 problem, solve 2 next time :) |
| CF 825 | Oct 10th | 7:35 | 3829(131st best so far) | Very good job skipping C2 and did D |
| CF 824 | Oct 2nd | 7:35 | 3593(192nd best so far) | took too long to solve A and B |
| CF 821 | Sept 19th | 7:35 | 3772 | bruh actually didn't think of dp for D2 |
| CF 819 | Sept 6th | 7:35 | 2980 | too slow, clear array for every test case |
| CF 813 | August 13th | 7:35 | 2876 | didn't solve D :( |
| CF 812 | August 6th | 7:35 | 2806 | didn't solve D :( |
| CF Edu_133 | August 4th | 7:35 | 3 | didn't solve C, I am a failure :( |
| CodeTon 2 | July 31st | 7:05 | 3167 | Do problems faster |
| CF 804 | July 4th | 7:35 | 2732 | Didn't solve D :( |
| CF 803 | June 28th | 7:35 | 1857 | got hacked :( |
| DMOPC | June 27th | 9:00 | 235 | failed to solve P2, actually took 2 hour to think, brain is so slow |
| CF Global 21 | Jun 25th | 7:35am | 5148(first time solve 5 problems!!!) | made such a stupid mistake for E |
| CF 801 | Jun 18th | 7:35am | 2071 | picked the wrong root |
| CF Edu_130 | Jun 12th | 7:35am | 4/6 | Too many wrong subs!!! |
| CF 796 | Jun 3rd | 7:35am | 2455 | Got trolled by C, should've looked at E |
| CF 795 | May 31st | 7:35am | 3592 | should've checked C before submitting |
| ACSL Final | May 28th | whole day | 35(Silver Medal) | problem so cancer |
| CF Edu 129 | May 23rd | 7:35am | 3 | you win some, you lose some |
| mBit | May 22nd | 10am | 2/10 | should've looked at the leaderboard to do easier problems |
| CF 793 | May 22nd | 7:35 | 4151(211th best so far) | I shouldnt've made 3 wrong sub for C |
| CF 789 | May 8th | 7:35 | 3081(266th best so far) | didn't solve D :( |
| CF 788 | May 6th | 7:35 | 4021 | actually failed A cause didn't put equal sign |
| CF 785 | Apr 30th | 7:35 | 2457 | really close to solve D |
| DMOPC Apr | Apr 24th | 9:00 | 210 | too slow debugging for P2 |
| CF 782 | Apr 17th | 7:35 | 3197(482nd best so far) | too slow, made so many WA on B |
| MALD 1 | Apr 16th | 9:00 | 310 | actually failed C Orz |
| USACO US Open 2022 Platinum | Mar 28th | 6:00 | 0 | Orz Orz Orz |
| USACO US Open 2022 Gold | Mar 27th | 1:00 | 1000 | I love Bessie!!! |
| CF Edu 125 | Mar 22nd | 7:35am | 3 problems | need improvement |
| Google Kickstart | Mar 19th | 9:00pm | 58 | throw less template, wrong manacher alg |
| SAC Code Challenge 4 | Mar 13th | 9:00 | 500(AK) | too slow debugging |
| CF 777 | Mar 11 | 6:35 | 2707 | fail to consider some cases for D |
| USACO 2022 Feb | Feb 25th-28th | 9:00 | 531 | get better at expected dp |
| CF 772 | Feb 20th | 6:35 | 4076(best so far 558th) | very good in terms of accuracy, but need improvement on time |
| CCC Senior | Feb 16th | 8:00 | 43 | I shouldn't have focused on S5, I am actually bad |
| DMOPC 21 Feb | Feb 10th - Feb 14th | 9:00 | 52 | P4 use bfs instead of dfs, go from the point not on path |
| CF 770 | Feb 6th | 6:35am | 2844 | look at parity |
| USACO 2022 Jan | Jan 28th - Jan 31st | 9:00 | 438 | so clooooose to plaaaat |
| An Animal Contest 5 | Jan 21th - Jan 24th | 9:00 | 410 (8th best so far) | keep it up, should've looked at P5 more |
| DMOPC Jan | Jan 13th - Jan 17th | 9:00 | 220 | should've done P3, instead of focusing on P5 |
| Mock CCC Senior 2 | Jan 2 - Jan 16th | 9:00 | 45 | could've done P3, overcomplicated it |
| Hello 2022 | Jan 3rd | 6:35am | 2140 | I should just start from D next time |
| BSSPC 21 Senior | December 26th - December 29th | 9:00 | 330 (15th place best so far) | think of out of bound earlier when debugging |
| An Animal Contest 4 | December 23rd - December 27th | 9:00 | 340 | should've got full for problem 4 |
| DMOPC December | December 17th - December 20th | 9:00 | 205 | left the last hour, should've been able to solve P3 |
| CF Deltix Autumn | Nov 28th | 6:35 - 8:05 | 3680 | For D, I thought too much, should've just read data size more carefully |
| CF 756 | Nov 25th | 6:35 - 8:50 | 4/8 | Got hacked for E1, F considered an extra step that is wrong |
| DMOPC November | November 12th - 15th | 9:00 | 210 | Should've finished first problem quicker |
| DMOPC October | October 8th -11th | 9:00 | 230 | should've attempted interactive, for problem 4 should've known how to do it |
| CF 747 | Oct 8th | 7:35 - 9:35 | 2764 | too dumb, too slow |
| CF 746 | Oct 3rd | 7:35 - 9:35 | 1210 | very sad that I missed on condition in the if statement for C |
| CF 742 | Sept 5th | 7:35 - 9:35 | 2921(first time solve 2250) | Good thing I solved E |
| DMOPC September | Sept 4th | 9:00 - 9:00 | 200 | I need to learn interactive problems! |
| CF Deltix21 | Aug 29th | 7:35 - 10:35 | 1298 | Need more practices! |
| CF 741 | Aug 26th | 7:35 - 9:35 | 1276 | Think case by case, and be patient when doing rough works |
| CF 740(div 2) | Aug 24th | 7:35 - 10:05 | 3678(598th/best so far) | don't get stuck on using segment when you can use prefix sum |
| Kickstart round E | Aug 21st | 8:30 - 11:30 | 1062th place | this one is hard |
| CF 739 | Aug 18th | 7:35am | 4/7 | Try to check answer before submission next time |
| CF 738 | Aug 15th | 7:35am | 3254/best so far(798th) | Should do questions faster and made one false submission |
| CF 737 | Aug 9th | 7:35am | 1330 | My brain too slow, do those questions faster |
| An Animal Contest 3 | Aug 3rd | 9:00pm | 400/800 | do questions faster, at least got back to purple |
| CF Edu_112 | July 30th | 7:35am | 3/6 | Getting back some skills after undergone 20 days of hell |
| CF 728 (Div 2) | Jne 24th | 8:35 am | 2342 | could've completed them faster |
| CF 727 | June 20th | 3:05 am | 2108 | Almost got the fourth question, could've finished problems quicker |
| DMOPC 21' June | June 18th - June20th | 9:00 am | 120 | For the second question I don't know how to output answers clockwise |
| CF LATOKEN | June 13 | 8:35 am | 2366 | Too dumb to do interactive problem. Also remember to check long long before submission |
| DMOPC '21 May Contest | May 28 - May 30 | 9:00 am | 300 | question 4 USE SET I am so dumbbbbb |
| An Animal Contest 2 | May 7th - May 10th | 9:00 pm | 230 | should've done question 3 |
| DMOPC '21 April Contest | April 23 2021 - April 25 2021, 2021 | 21:00 PDT - 21:00 PDT | 200 | Should've gotten partial for question 3 |
| Google Kickstart 2021 round B | April 18th | 4:00am | 41/100 | good thing I got partial for C and D |
| Codeforces Round #713 | April 10th | 7:35am | 4/7 | I ran out of time |
| USACO 2021 US Open | April 2nd | 9:00am | 394/1000 (Gold) | P2 and P3 are out of my skill range currently |
| USACO 2021 Feburary | Feb 17th | 9:00am | 800/1000 (Silver) | P2 make the array bigger |
| USACO 2020 December | Dec 18th | 9:00am | 900/1000 (Bronze) | Final question using discretization |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| CSPS 2021 | T2 | complete | dp, using multiple states | *** |
| CSPJ 2022 | T4 | complete | dp | ** |
| CSPJ 2022 | T3 | complete | stack | ** |
| CSPJ 2022 | T2 | complete | binary search | ** |
| CSPJ 2022 | T1 | complete | don't be dumb | * |
| CSPS 2022 | T3 | complete | kind of hashing, simplify the problem | **** |
| CSPS 2022 | T1 | complete | travel two places, use math to combine cases | *** |
| CSPS 2022 | T2 | complete | use multiple sparse tables | ** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| HDU | Winner Prediction | complete | greedily let 1 win for every m2 games containing 1, dinic all other games | *** |
| HDU | Matryoshka Doll | complete | dp | *** |
| HDU | Origrimmar | complete | answer is the same regardless, just simulate | * |
| HDU | backpack | complete | bitset, dp | *** |
| HDU | ball | complete | bitset, sorting | *** |
| HDU | copy | complete | do operation in reverse, bitset | *** |
| HDU | Link with Level Editor II | complete | two pointer, matrices | *** |
| HDU | Shinobu loves trips | complete | math | ** |
| HDU | Luxury cruise ship | complete | do dp till the LCM of all three numbers | *** |
| HDU | Static Query on Tree | complete | segtree, hld, binary lifting | *** |
| HDU | alice bob | complete | 2 Ns can be viewed as 1 N - 1 | ** |
| HDU | random | complete | understand expected value | * |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| 2022 Spring | P7 | complete | knapsack | ** |
| 2022 Spring | P9 | complete | get result with first time, check with all other times | *** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| NOI 2009 | P4 | complete | minimum cut, get rid of cycle with tarjan | *** |
| NOI 2008 | P3 | complete | max flow, assume hire inf employers and build graph | *** |
| NOI 2006 | P4 | complete | minimum cut, flow means profit lost | **** |
| NOIP 2015 | Substring | complete | dp, rolling array | *** |
| NOIP 2016 | toy | complete | easy implementation | ** |
| NOIP 2016 | classroom | complete | expected value dp | *** |
| NOIP 2016 | earthworm | complete | maintain three values, get max every time | *** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| C2 | P6 | complete | li chao tree, convex hull trick | **** |
| C2 | P4 | complete | prim | ** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| C7 | P5 | complete | find diameter | *** |
| C7 | P3 | complete | binary search or two pointer for the position using and not using portal | ** |
| C7 | P2 | complete | reorganize the tree | * |
| C7 | P1 | complete | case by case | * |
| C6 | P3 | complete | math, frequency array | *** |
| C5 | P6 | complete | centroid decomposition, LCA, dijkstra | ***** |
| C5 | P5 | complete | fenwick, two pointer | **** |
| C5 | P4 | complete | binary search, move big number first | *** |
| C5 | P3 | complete | dfs with range | ** |
| C5 | P2 | complete | query 1 with all other numbers | * |
| C5 | P1 | complete | super easy implementation | * |
| C4 | P4 | complete | throw l bananas, throw randomly doesn't matter, but last throw go to f | ** |
| C4 | P3 | complete | choose a reference coordinate, if two points with the same slope shoot to the same reference, then they form a pair | ** |
| C4 | P2 | complete | maintain a prefix lcm, and binary search | *** |
| C4 | P1 | complete | super easy implementation | * |
| C3 | P4 | complete | greedy, a bit of math | *** |
| C3 | P3 | complete | sorting, greedy | ** |
| C3 | P2 | complete | greedy | * |
| C3 | P1 | complete | implementation | * |
| C2 P1 | Koala Konundrum | complete | greedy | ** |
| C2 P2 | Koala Party | complete | case enumeration | ** |
| C2 P3 | Koala Balloon | complete | binary search, prefix sum | *** |
| C2 P4 | Koala Gambling | complete | case enumeration, greedy | *** |
| C2 P5 | Koala Carnival | complete | Segment Tree, two pointer, binary search | ***** |
| C2 P6 | Koala Transport System | complete | heavy light decomposition | *** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| 22 Round B | Problem C | complete | interval dp, a dimension to maintain right or left it was transitioned | *** |
| 22 Round B | Problem B | complete | brute force | * |
| 22 Round B | Problem A | complete | math | * |
| 22 Round A | Problem C | complete | bitmask dp | *** |
| 22 Round A | Problem B | complete | math | * |
| 22 Round A | Problem A | complete | super easy implementation | * |
| 21 Round H | Problem B | complete | fake dp | * |
| 21 Round H | Problem A | complete | Greedy | * |
| 21 Round F | Problem A | complete | binary search | * |
| 21 Round E | Problem C | complete | Disjoint Set Union, merge palindrom elements | *** |
| 21 Round E | Problem A | complete | shuffle string by swaping | * |
| 21 Round B | Problem D | complete | Segment Tree, offline/unsynchronized calculation, dfs | **** |
| 21 Round B | Problem C | complete | Maximum interval between primes | ** |
| 21 Round B | Problem B | complete | Pre-fix Sum, total three cases | ** |
| 21 Round B | Problem A | complete | enumeration | * |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| DMOPC 19 c3 | P4 | complete | dp | ** |
| DMOPC 19 c7 | P4 | complete | matrix | *** |
| DMOPC 19 c7 | P5 | complete | cdq divide and conquer | *** |
| DMOPC 16 c4 | P4 | complete | Mo's algorithm | ** |
| DMOPC 19 c4 | P3 | complete | dp | ** |
| DMOPC 19 c6 | P4 | complete | map on fenwick tree, don't use segment | ** |
| DMOPC 15 c5 | P5 | complete | don't use HLD, use fenwick + Euler tour | ** |
| DMOPC 22 c2 | P2 | complete | inverse pair | ** |
| DMOPC 22 c2 | P3 | complete | use graph theory, topological sort | *** |
| DMOPC 18 c3 | P4 | complete | find centroid of all z, then sum of depth | *** |
| DMOPC 19 c2 | P3 | complete | 20 fenwicks | ** |
| DMOPC 21 c10 | P2 | complete | either not move 1, not move 2, or move 1 and 2 | ** |
| DMOPC 21 c10 | P1 | complete | basic stack | * |
| DMOPC 20 c7 | P5 | complete | literally samething as NOI06p4, just gotta do ll | **** |
| DMOPC 21 Apr | P2 | complete | odd even have same sum | ** |
| DMOPC 21 Apr | P1 | complete | easy multiset | ** |
| DMOPC 21 Mar | P2 | complete | linked list | ** |
| DMOPC 21 Feb | P4 | complete | A to B cover up C or D | *** |
| DMOPC 21 Feb | P3 | complete | bfs with pq | ** |
| DMOPC 21 Feb | P2 | complete | greedy, just consecutive 0s are important | ** |
| DMOPC 21 Feb | P1 | complete | greedy | * |
| DMOPC 21 Jan | P2 | complete | game theory dp, only three possible cases | *** |
| DMOPC 21 Jan | P1 | complete | odd number first, then even number | ** |
| DMOPC 21 Jan | P1 | complete | number theory | * |
| DMOPC 21 Dec | P3 | complete | nothing to do with coding, pure math | ** |
| DMOPC 21 Dec | P2 | complete | prime sieving | * |
| DMOPC 21 Dec | P1 | complete | geometry and slopes | * |
| DMOPC 21 Nov | P4 | complete | use DSU to merge groups, use segtree that store sizes for each value | **** |
| DMOPC 21 Nov | P2 | complete | only consider separate into two | *** |
| DMOPC 21 Nov | P1 | complete | interactive big brain | ** |
| DMOPC 21 Oct | P4 | complete | monotone queue dp, calculate l and r in O(n) | *** |
| DMOPC 21 Oct | P3 | complete | randomize all the unknown number | *** |
| DMOPC 21 Oct | P2 | complete | two arrays, keep track of index and value | ** |
| DMOPC 21 Oct | P1 | complete | binary search, prefix sum | *** |
| DMOPC 16 c4 | P5 | complete | dsu, dfs | *** |
| DMOPC 21 Sept | P3 | complete | interactive, merge two disjoint sets and redirect all edges in each query | *** |
| DMOPC 21 Sept | P2 | complete | remove as "consecutive" as possible | ** |
| DMOPC 21 Sept | P1 | complete | greedy, go by two each time | * |
| DMOPC 21 June | P4 | complete | heavy light decomposition, store how many son nodes are safe | *** |
| DMOPC 21 June | P2 | complete | store lines in a set with pair<pii, pii> | *** |
| DMOPC 21 May | P3 | complete | dfs, reverse graph, greedy | *** |
| DMOPC 21 May | P2 | complete | greedy | *** |
| DMOPC 21 May | P1 | complete | kind of two pointer, greedy | ** |
| DMOPC 15 Contest 2 | Personal Assistant | complete | knapsack problem, discretization, binarySearch | *** |
| DMOPC 20 Contest 5 | Home Row | complete | enumeration | * |
| DMOPC 20 Contest 5 | On the Clock | complete | enumeration, double inacurrate | ** |
| DMOPC 20 Contest 4 | Beautiful Grid | complete | Greedy, enumeration | *** |
| DMOPC 20 Contest 4 | Roving Roombas | complete | Block Matrix, binarySearch | **** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| wlxsq | 华盛顿的斧子 | complete | DSU, kruskal | *** |
| wlxsq | 绝地求生 | complete | segtree | *** |
| wlxsq | 红叶配绿花 | complete | binary search, subtract red by a value | **** |
| wlxsq | 招待 | complete | ternary | ** |
| wlxsq | 小说 | complete | two dimensional dijkstra | ** |
| wlxsq | DNA | complete | easy hashing | ** |
| wlxsq | 种树 | complete | dp | *** |
| wlxsq | 旅游景点 | complete | graph don't have to be connected, lca, connect edges not connected to node 1 ~ k first | ** |
| wlxsq | calc | complete | binary lifting | **** |
| wlxsq | travel | complete | dfs | * |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| USACO 2022 Dec Platinum | P1 | complete | only run dfs if going through edge is better, this solution probably cheese | *** |
| USACO 2022 Dec Platinum | P2 | complete | dsu, merge small to big | *** |
| USACO 2021 Jan Platinum | P1 | complete | segtree maintain the number of numbers not swappable before the current number | *** |
| USACO 2020 Jan Platinum | P1 | complete | dsu, dp on DAG | ** |
| USACO 2019 Dec Platinum | P2 | complete | Euler tour, remove operations using bst | *** |
| USACO 2021 Dec Platinum | P1 | complete | segment tree store graph, build reverse graph, create super node, make sure every given segment is a single point | **** |
| USACO 2017 Feb Platinum | P2 | complete | segment tree to store the dp state with the maximum roads you can have with last road on that position | **** |
| USACO 2019 Dec Platinum | P1 | complete | interval dp | **** |
| USACO 2021 US Open Platinum | P1 | complete | segment tree to calculate number of sets for all l as r is enumerated | **** |
| USACO 2021 Feb Platinum | No time to cry | complete | answer equal to length minus pairs of same color such that they can be drawn with one bruh stroke | *** |
| USACO 2020 Dec Platinum | Sleeping cows | complete | dp, add dimensions | ***** |
| USACO 2017 Jan Platinum | Promotion Counting | complete | Persistent tree, dfs order | ***** |
| USACO 2017 Feb Platinum | Why did the Cow Cross the Road I | complete | Fenwick, shift both a and b | *** |
| USACO 2016 Feb Platinum | Fenced In | complete | Greedy, MST, open up all row or col at once | ***** |
| USACO 2015 Dec Platinum | Max Flow | complete | Lazy, sparse table lca | *** |
| USACO 2015 Jan Gold | P3 | complete | layered graph, tarjan | *** |
| USACO 2022 Dec Gold | P1 | complete | dp, sort according to x, set x to 0 after using it as much as possible | *** |
| USACO 2022 Dec Gold | P2 | complete | monotonic set, use segtree instead of std::set | *** |
| USACO 2022 Dec Gold | P3 | complete | greedy forward, dsu backward | *** |
| USACO 2017 Open Gold | P3 | complete | pick interval end earliest, use linked list to check whether or not possible | *** |
| USACO 2017 Jan Gold | Hoof, Paper, Scissors | complete | prefix mx | ** |
| USACO 2006 October Gold | Building the Moat | complete | convex hull | ** |
| USACO 2007 Open Gold | Dining | complete | dinic, make each cow an edge | *** |
| USACO 2022 Open Gold | P3 | complete | maintain max l and min r for all subtrees | **** |
| USACO 2022 Open Gold | P2 | complete | standard dp, 0 and 1 are special cases | *** |
| USACO 2022 Open Gold | P1 | complete | realise two inequalities and use map | **** |
| USACO 2022 Feb Gold | P3 | complete | only connect nodes from the same row once | ** |
| USACO 2022 Jan Gold | P2 | complete | do operations in reverse | *** |
| USACO 2022 Jan Gold | P1 | complete | dynamic programming, prefix sum | *** |
| USACO 2018 Dec Gold | fine dining | complete | dijkstra, spfa, create a super node | *** |
| USACO 2021 Dec Gold | pair up | complete | dp, binary search | **** |
| USACO 2021 Dec Gold | HILO | complete | monotonic stack, enumerate rank, and then store position | **** |
| USACO 2019 Jan Gold | sleepy | complete | shortest length is the total length subtract longest decreasing suffix | *** |
| USACO 2019 Jan Gold | poetry | complete | dp, at last, calculate number of ways for one rhyme class, then multiply all together later | *** |
| USACO 2019 Jan Gold | shortcut | complete | dijkstra, build the tree last, very important, otherwise order is messed up | *** |
| USACO 2019 Feb Gold | barn painting | complete | 2d lazy, enumerate 2 column and use prefix sum, two rectangle most have one axis to separate | **** |
| USACO 2019 Feb Gold | dishes | complete | binary searching, simulation | *** |
| USACO 2020 Feb Gold | delegation | complete | dp, only one path can lead up the tree, all rest need to be matched | *** |
| USACO 2020 Dec Gold | P3 | complete | two pointers, flip the coordinates for easier implementation | **** |
| USACO 2019 US Open Gold | P3 | complete | enumerating how many 1s is passed from left to right and vise versa | *** |
| USACO 2019 US Open Gold | P1 | complete | dp, sparse table | ** |
| USACO 2019 US Open Gold | P2 | complete | minimum spanning tree, the kth biggest edge, prim O(n^2) | *** |
| USACO 2020 Jan Gold | threesum | complete | interval dp, consider two end points to update, use array instead of unordered_map, delete only the added | *** |
| USACO 2020 Jan Gold | boards | complete | segment tree, remember to sort by y as well, write transition out | *** |
| USACO 2020 Jan Gold | Time is Mooney | complete | dp add dimension, reverse graph, remember to initialize | ** |
| USACO 2021 Feb Gold | Stone Game | complete | game theory, mirror moves, find odd occurrence | **** |
| USACO 2019 Dec Gold | moortal cowmbat | complete | dp, floyd algorithm, prefix sum | *** |
| USACO 2019 Dec Gold | milk_pumping | complete | dijkstra's algorithm, another dimension for flow rate | *** |
| USACO 2021 Jan Gold | telephone | complete | only connect the closest breeds, connecting to further cows will only produce same result | *** |
| USACO 2021 Jan Gold | Uddered But Not Herd | complete | bitmask dp, only 20 char, in dp statement, choose a letter to be the most afterward | **** |
| USACO 2020 Dec Gold | Bovine Genetics | complete | dynamic programming, express the last two segments in dp statement | **** |
| USACO 2015 Feb Gold | Censoring | complete | Hashing | **** |
| USACO 2019 Feb Gold | Cow Land | complete | easy heavy light decomposition | *** |
| USACO 2020 Feb Gold | Exercise | complete | knapsack problem, add to n, sum of LCM | **** |
| USACO 2020 Feb Gold | Help Yourself | complete | lazy, each segment contribute 1 when no other segment cover its beginning | **** |
| USACO 2020 Feb Gold | TimeLine | complete | SPFA, remember to include the property less than m | **** |
| USACO 2020 US Open Gold | Favorite Color | complete | disjoint set union, merge edges | *** |
| USACO 2020 US Open Gold | Hair Cut | complete | fenwick, each time add inverse pair end with j | *** |
| USACO 2007 Nov Gold | Cow Relays | complete | binary rate multiply, floyd algorithm | **** |
| USACO 2003 Fall Gold | Puck Just Me | complete | Tarjan | **** |
| USACO Training | Bessie come Home | complete | dijkstra, reverse graph | ** |
| USACO Training | Riding the Fence | complete | Euler Circuit, Hierholzer's Algorithm | *** |
| USACO 2005 Dec Gold | Layout | complete | Bellman-Ford, -1 for negative ring, -2 for not connected. turn Differential constraint into graphs | **** |
| USACO 2011 Open Gold | Mowing the Lawn | complete | monotone queue dynamic programming | *** |
| USACO 2008 Jan | cow race | complete | floyd algorithm | *** |
| USACO 2021 Open Gold | Portals | complete | Kruskal, turn cycles into vertices | **** |
| USACO 2006 Nov Gold | cowfood | complete | bitmasking, dynamic programming | *** |
| USACO 2016 Feb Gold | Fenced In | complete | MST algorithm, separate into horizontal and vertical lines | **** |
| USACO 2019 Dec Gold | Milk Visits | complete | Sparse Table, offline/unsynchronized calculation | **** |
| USACO 2021 US Open Gold | United Cows of Farmer John | complete | enumerate r, binary search l, revisited with Fenwick tree | ** |
| USACO 2008 Nov Gold | Switching light | complete | Segment Tree, interval update | ** |
| USACO 2017 Jan Gold | Balanced Photo | complete | Segment Tree, discretization | ** |
| USACO 2021 Feb Gold | Modern Art 3 | complete | Dynamic Programming | *** |
| USACO 2022 Dec Silver | P3 | complete | get an answer from adjacent, check the answer | ** |
| USACO 2022 Dec Silver | P2 | complete | game theory, realize formula | *** |
| USACO 2022 Dec Silver | P1 | complete | first send up, then send down | *** |
| USACO 2017 Dec Silver | P1 | complete | psa | ** |
| USACO 2021 Dec Silver | P3 | complete | lazy array | ** |
| USACO 2021 Dec Silver | P2 | complete | DSU, find length to 1 and n | ** |
| USACO 2020 Jan Silver | Loan_Repayment | complete | skipping repeated terms | *** |
| USACO 2018 Feb Silver | Snow Boots | complete | implementation | ** |
| USACO 2015 Feb Silver | Censoring | complete | Hashing | **** |
| USACO 2020 Jan Silver | Berry Picking | complete | greedy + enumerate berries in Elsie's buckets | *** |
| USACO 2019 Dec Silver | Milk Visits | complete | Sparse Table | ** |
| USACO 2021 US Open Silver | Do You Know ABCs? | complete | enumeration, brute force | ** |
| USACO 2021 Feb Silver | Comfortable Cows | complete | implementation | * |
| USACO 2021 Feb Silver | Year of the Cows | complete | Greedy | * |
| USACO 2021 Feb Silver | Just Green Enough | complete | Monotone Stack | **** |
| USACO 2021 Jan Silver | Dance Mooves | complete | DFS, Graph Theory | ** |
| USACO 2021 Jan Silver | No Time to Paint | complete | Prefix Sum, Suffix Sum | *** |
| USACO 2021 Jan Silver | Spaced Out | complete | enumeration, knowing two lines give the whole grid | *** |
| USACO 2020 Dec Silver | Cowntagion | complete | Graph Theory, Tree | ** |
| USACO 2020 Dec Silver | Rectangular Pasture | complete | 2D Prefix - sum, Multiplication Principle | **** |
| USACO 2020 Dec Silver | Stuck in a Rut | complete | Discretization, priority_queue, Topological order | ***** |
| USACO 2020 Feb Silver | P1 | complete | binary lifting | ** |
| USACO 2020 US Open Bronze | P2 | complete | don't be dumb | * |
| USACO 2016 US Open Bronze | P1 | complete | psa | * |
| USACO 2020 Dec Bronze | Stuck in a Rut | complete | Discretization, priority_queue | ***** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| CCO 17 | P4 | complete | sort pillar from greatest to smallest, bitmask dp | *** |
| CCO 16 | P5 | complete | linesweep, segtree | *** |
| CCO 15 | P6 | complete | inclusion principle, 2d stuffs | *** |
| CCO 19 | P2 | complete | heap, simulation, dsu | *** |
| CCO 08 | P3 | complete | brute force checking, use dep and sz to optimize | ** |
| CCO 03 | P6 | complete | tarjan | ** |
| CCO 09 | P5 | complete | segtree, merge operations | ** |
| CCO 18 | P3 | complete | dp, case by case | *** |
| CCO 18 | P2 | complete | cancerous thinking | ** |
| CCO 19 | P1 | complete | bitmask dp | ** |
| CCO 19 | P5 | complete | same as USACO Dec 2022 | ** |
| CCO 01 | P6 | complete | easily check "will become", use dinic to check "may"/"will not" | *** |
| CCO 11 | P4 | complete | multiset, greedy | * |
| CCO 20 | P1 | complete | coordinate compression, difference array | ** |
| CCO 17 | P5 | complete | same as buying everything first, assume every item lower than the want value of current one has been obtained | *** |
| CCO 21 | P2 | complete | brute force dfs | *** |
| CCO 21 | P1 | complete | separate into two sets, one appear more than 100 times, and another less than 100 times, swap = inversion pair | *** |
| CCO 14 | P5 | complete | easy greedy | ** |
| CCO 20 | P2 | complete | number of swap = number of inversion, from last element, search for maximum spot to place | *** |
| CCO 14 | P2 | complete | run dijkstra from A and B(reverse graph), calculate offline | ** |
| CCO 18 | P4 | complete | do two binary searches together | *** |
| CCO 16 | P6 | complete | splay | **** |
| CCO 05 | P4 | complete | use bitset, prime seiving | ** |
| CCO 15 | P6 | complete | 5 dimension dp, super cancer | *** |
| CCO 22 | P2 | complete | first check YES/NO, stack to buy umbrella, difference array | *** |
| CCO 05 | P5 | complete | dp | ** |
| CCO 22 | P1 | complete | two pointer/binary search, find cycle | ** |
| CCO 15 | P4 | complete | topological order | ** |
| Mock CCO 18 | P2 | complete | greedy, break into x + t, x - t | *** |
| Mock CCO 18 | P3 | complete | second shortest path | *** |
| CCO 12 | P2 | complete | second shortest path | *** |
| CCO 98 | P1 | complete | big number | * |
| CCO Mock 18 | P4 | complete | check negative cycle with bellman ford | ** |
| CCO 2010 | P2 | complete | dp on trees, knapsack | *** |
| CCO Mock 19 | P1 | complete | reverse merge | *** |
| CCO 2014 | P3 | complete | dp on trees, knapsack | *** |
| CCO 2014 | P1 | complete | dp | ** |
| CCO 2010 | P6 | complete | binary lifting | *** |
| CCO Prep | packing up | complete | convex hull trick, use __int128 | **** |
| CCO 2018 | P1 | complete | LCS | ** |
| CCO 2013 | P3 | complete | find half of perimeter | **** |
| CCO 2015 | P2 | complete | Bitmasking | **** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| CCC 2023 | J5 | complete | easy dfs, optional hashing | ** |
| CCC 2023 | S4 | complete | sort edge based on C, remove based on dijkstra | ** |
| CCC 2023 | S3 | complete | case by case, cancerous | *** |
| CCC 2023 | S2 | complete | enumerate middle and expand | * |
| CCC 2023 | S1 | complete | trivial | * |
| CCC 2022 | S5 | complete | cancerous tree dp | *** |
| CCC 2022 | S4 | complete | psa, cancerous counting | *** |
| CCC 2011 | S4 | complete | maximum flow | ** |
| CCC 2022 | S3 | complete | put numbers in increasing order | *** |
| CCC 2022 | J5 | complete | sorted based on x axis | *** |
| Mock CCC 2022 1 | S4 | complete | Mo algorithm, reset left point, only expanding, don't use vectors or hashing structure, just array | **** |
| Mock CCC 2022 2 | S3 | complete | hashing | *** |
| CCC 2002 | S4 hard | complete | segment tree, change result from i to the rightmost element greater than one | *** |
| CCC 2020 | S5 | complete | dp, only last position of a burger matters, if need to randomly choose, the subset is always the same | **** |
| CCC 1996 | S5 | complete | easy minimum segtree | *** |
| CCC 2003 | S5 | complete | mst, dfs | *** |
| CCC 2019 | S5 | complete | divide and conquer, best solution for sub triangle is when it crosses the centroid (2/3) n | ***** |
| CCC 2020 on DMOJ | J4_hard | complete | Rolling Hash | **** |
| CCC 2010 | S5 | complete | DP on a tree, trade memory for time | *** |
| CCC 2003 | S4 | complete | if all substrings of length X are distinct, then all substring of X+1 should also be distinct | *** |
| CCC 2009 | S4 | complete | dijkstra | ** |
| CCC 2011 | S4 | complete | disjoint set, reading input correctly | *** |
| CCC 2010 | S3 | complete | binary search | ** |
| CCC 2011 | S5 | complete | bitwise operation, bfs | ** |
| CCC 2019 | S4 | complete | Dynamic Programming, Sparse Table, Greedy | ***** |
| CCC 2019 | S4v2 | complete | segment tree, subtract by infinity, no worry about days | **** |
| CCC 2017 | S5 | complete | block matrix, block[l] == block[r] not l == r | ***** |
| CCC 2018 | S5 | complete | Calculate Flights and Portals separately, link all portals/flights except those already connected | ***** |
| CCC 2012 | S4 | complete | Brute Force, BFS, java is op(passing array into queue), c++ pointer | *** |
| CCC 2021 | S5 | complete | Greedy, Segment Tree, lazy, lcm, gcd | ***** |
| CCC 2013 | S4 | complete | turn situation into a graph | * |
| CCC 2013 | S3 | compelte | enumeration | * |
| CCC 2019 | J5 | complete | run dfs twice | *** |
| CCC 2016 | S5 | complete | Binary rate multiply, xor | ***** |
| CCC 2015 | S5 | complete | Dynamic Programming, Greedy, four dimensional dp state | **** |
| CCC 2017 | S4 | complete | Kruskal algorithm, MST problem, run MST twice to see if a non-active pipe can be replaced | **** |
| CCC 2014 | S4 | complete | Discretization | *** |
| CCC 2014 | S5 | complete | Dynamic Programming, save the result last time to avoid collision with other results | **** |
| CCC 2020 | S4 | complete | enumeration, greedy | **** |
| CCC 2020 | S3 | complete | Rolling Hash, compute hash value twice | **** |
| CCC 2018 | S4 | complete | Dynamic Programming, multiplication | *** |
| CCC 2021 | S1 | complete | implementation, double is not accurate | * |
| CCC 2021 | S2 | complete | using two arrays instead of a 2d array | * |
| CCC 2021 | S3 | complete | Prefix Sum, Binary Search, Math | **** |
| CCC 2021 | S4 | complete | Reversed graph, Dijkstra, priority_queue | *** |
| CCC 2015 | S4 | complete | SPFA, add a dimension | ** |
| CCC 2002 | S4 | complete | Doing dp in an interval | *** |
| CCC 2001 | S3 | complete | Disjoint Set | ** |
| CCC 2009 | S3 | complete | toxic | * |
| CCC 2005 | S5 | complete | fenwick | ** |
| CCC 2008 | S5 | complete | game theory dp | ** |
| Source | Problems | Status | Skills needed | rating |
|---|---|---|---|---|
| IOI 2015 | P4 | complete | use log value to compare | ** |
| IOI 2002 | P4 | complete | convex hull trick | *** |
| IOI 2006 | P2 | complete | use fenwick on rmq | *** |
| IOI 1998 | P4 | complete | coordinate compression, line sweep, difference array | ** |
| IOI 2010 | P3 | complete | binary search, prefix sum | *** |
| IOI 2004 | Empodia | complete | montonic stack to store min and max, two nodes is okay if value - index is the same | *** |
| IOI 1996 | Network of Schools | complete | Tarjan scc | *** |
| IOI 1994 | The Triangle | complete | standard dp | * |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| CF 604 | E | complete | minimize |
**** |
| CF 884 | D | complete | dp, get all factors | ** |
| CF 884 | C | complete | dp, odd length can be 0 | ** |
| CF 292 | D | complete | dsu on tree, diameter of tree | *** |
| CF Beta 3 | D | complete | put all ), if not okay, replace with cheapest ( | ** |
| CF 722 | D | complete | add edges between adjacent nodes | **** |
| CF 872 | D2 | complete | count number of occurence of edges, + 1 to get result for nodes | *** |
| CF 873 | E | complete | manacher + segtree + dp | *** |
| CF 200 | D | complete | heavy light decomp | ** |
| CF Edu_111 | E | complete | binary search, bitmask dp | *** |
| CF 852 | F | complete | binary search for left, everytime decrease by average, use segment tree maintain answer for l | **** |
| CF 845 | E | complete | binary search, scc, dsu | *** |
| CF 845 | D | complete | expected value | *** |
| CF 845 | C | complete | sort, two pointer | ** |
| CF 845 | B | complete | math, all permutation are the same | * |
| CF 845 | A | complete | trivial | * |
| CF Hello 2023 | F | complete | odd tree makes no difference even can be turned to 0 | *** |
| CF Hello 2023 | D | complete | monotonic stack, dsu | ** |
| CF Hello 2023 | C | complete | use min or max instead of current element | ** |
| CF Hello 2023 | B | complete | do some algebra | * |
| CF Hello 2023 | A | complete | trivial | * |
| CF Polynomial Round 2022 | E | complete | binary lifting | ** |
| CF Polynomial Round 2022 | D | complete | two pointer | ** |
| CF Polynomial Round 2022 | C | complete | observation | ** |
| CF Polynomial Round 2022 | B | complete | sort | ** |
| CF Polynomial Round 2022 | A | complete | change everytime see 1 | * |
| CF 832 | D | complete | case by case | *** |
| CF 832 | C | complete | whoever have the minimum | ** |
| CF 832 | B | complete | don't be dumb | * |
| CF 832 | A | complete | don't be dumb | * |
| CF 831 | E | complete | simple dp | ** |
| CF 831 | D | complete | only 2 blank spaces are required | ** |
| CF 831 | C | complete | let a number be in 2, one of the other number must be either max or min | ** |
| CF 831 | B | complete | long long | * |
| CF 831 | A | complete | don't be dumb | * |
| CF 830 | C | complete | realize f(l, r) <= f(l, r + 1), enumerate first 32 non-zero L because of pigeon hole, binary search r | *** |
| CF 830 | B | complete | be careful of 0 | * |
| CF 830 | A | complete | answer can only be 0, 1, 2 | * |
| CF 829 | E | complete | basic expected value | ** |
| CF 829 | D | complete | simple math | * |
| CF 829 | C | complete | group with previous one to change sign | ** |
| CF 829 | B | complete | greedy | * |
| CF 829 | A | complete | don't be dumb | * |
| CF Edu_138 | E | complete | turn into graph, dijkstra | *** |
| CF Edu_138 | D | complete | make sure to either mod or use __int128 | ** |
| CF Edu_138 | C | complete | binary search | * |
| CF Edu_138 | B | complete | don't be dumb | * |
| CF Edu_138 | A | complete | don't be dumb | * |
| CF 828 | F | complete | go to the next smallest number, do some math for median | *** |
| CF 825 | D | complete | group every consecutive two numbers, connect if 01 or 10 | *** |
| CF 825 | C1 | complete | segment tree + binary search | ** |
| CF 825 | B | complete | take lcm and check if it is okay | * |
| CF 825 | A | complete | don't be dumb | * |
| CF 824 | D | complete | enumerating, use set | ** |
| CF 824 | C | complete | dsu, implementation | ** |
| CF 824 | B | complete | math | * |
| CF 824 | A | complete | math | * |
| CF Global 22 | D | complete | topological order | *** |
| CF Global 22 | C | complete | logic | ** |
| CF Global 22 | B | complete | implementation | * |
| CF Global 22 | A | complete | implementation | * |
| CF 821 | D1 | complete | if not two consecutive, then always just use all y | ** |
| CF 821 | C | complete | set a[1] = a[n], then update accordingly | ** |
| CF 821 | B | complete | always a win follow by some lose | * |
| CF 821 | A | complete | don't be dumb | * |
| CF Edu_135 | D | complete | dp | ** |
| CF Edu_135 | C | complete | look at maximum | ** |
| CF Edu_135 | B | complete | pattern | * |
| CF Edu_135 | A | complete | easy | * |
| CF 819 | D | complete | dsu, use red to do a tree, remaining edge might form cycle, in that case, relink edges | *** |
| CF 819 | C | complete | logic | ** |
| CF 819 | B | complete | case by case | * |
| CF 819 | A | complete | case by case | * |
| CF Edu_134 | D | complete | bit by bit, every number in a, there must be a reverse in b | *** |
| CF Edu_134 | C | complete | for min, use two pointer, for max, find leftmost r such a[r] > b[r - 1] | *** |
| CF Edu_134 | B | complete | check border | * |
| CF Edu_134 | A | complete | don't be dumb | * |
| CF 813 | C | complete | greedy | ** |
| CF 813 | B | complete | swap adjacent | * |
| CF 813 | A | complete | easy | * |
| CF 812 | D | complete | interactive, eliminate 3 elements with 2 moves | *** |
| CF 812 | C | complete | dp | ** |
| CF 812 | B | complete | minimum must be on either side | * |
| CF 812 | A | complete | don't be stupid | * |
| CF Edu_133 | D | complete | dp, cannot make more than around sqrt(N) jumps | *** |
| CF Edu_133 | B | complete | don't be stupid | * |
| CF Edu_133 | A | complete | don't be stupid | * |
| CF 811 | G | complete | simple binary lifting | ** |
| CF 811 | E | complete | turn everything into 2 suffix and check modulo 20 | ** |
| CF 811 | D | complete | dp | ** |
| CF 811 | C | complete | pattern | * |
| CF 811 | B | complete | don't be dumb | * |
| CF 811 | A | complete | don't be dumb | * |
| CodeTon 2 | E | complete | simulate N times to remove middle 0s, topological sort add up all a | *** |
| CodeTon 2 | D | complete | subtracting two sequences | *** |
| CodeTon 2 | C | complete | simple math | ** |
| CodeTon 2 | B | complete | set up range | ** |
| CodeTon 2 | A | complete | check suffix | * |
| CF 810 | C | complete | just at least two columns for every color | ** |
| CF 810 | B | complete | basic thinking | * |
| CF 810 | A | complete | big brain observation | * |
| CF 809 | E | complete | LCA, segtree, dsu | **** |
| CF 809 | D1 | complete | get all numbers, go from small to big | ** |
| CF 809 | C | complete | odd even property | * |
| CF 809 | B | complete | odd even property | ** |
| CF 809 | A | complete | very easy implementation | * |
| CF 808 | D | complete | just simulate | *** |
| CF 808 | C | complete | compute backwards | *** |
| CF 808 | B | complete | number don't have to be distinct, ith gcd be i | ** |
| CF 808 | A | complete | gcd | ** |
| CF 807 | E | complete | turn into binary number add and sub 1s | *** |
| CF 807 | D | complete | remove duplicates to check, then store starting and ending position and subtract | *** |
| CF 807 | C | complete | record copying position, transition to the original string | *** |
| CF 807 | B | complete | always use the most front | * |
| CF 807 | A | complete | easy sorting | * |
| CF Edu_131 | D | complete | turn into intervals, sort based on right hand side | *** |
| CF Edu_131 | C | complete | binary search | ** |
| CF Edu_131 | B | complete | greedy | * |
| CF Edu_131 | A | complete | easy | * |
| CF 804 | C | complete | maintain l, r, two cases inside outside interval | ** |
| CF 804 | B | complete | repeat a pattern | ** |
| CF 804 | A | complete | if odd not possible, else two 0s and n/2 | * |
| CF 803 | D | complete | cut into two segments and delete swaps outside of current segment | ** |
| CF 803 | B | complete | add will only make it worse unless k = 1 | ** |
| CF 803 | A | complete | xor properties | * |
| CF Global 21 | E | complete | realize pattern is same as number of paths in a matrix, Fermat's little theorem | *** |
| CF Global 21 | D | complete | monotonic stack | *** |
| CF Global 21 | C | complete | divide all element by m as many times as possible and check whether simplified versions are equal | ** |
| CF Global 21 | B | complete | answer is 0, 1 or 2, remove 0s on the side check whether center have 0 | * |
| CF Global 21 | A | complete | or all value in a with z | * |
| CF 802 | D | complete | dp, find how long it first i pipes to fill first i first | *** |
| CF 802 | C | complete | difference array, greedy | ** |
| CF 802 | B | complete | math | * |
| CF 802 | A | complete | math | * |
| CF 801 | D | complete | gotta pick any root degree >= 3, and no need query root | *** |
| CF 801 | C | complete | yes if 0 between minimum and maximum | ** |
| CF 801 | B | complete | game theory | ** |
| CF 801 | A | complete | easy brute force | * |
| CF 800 | E | complete | dijkstra | *** |
| CF 800 | D | complete | simple tree dp | *** |
| CF 800 | C | complete | some logics | ** |
| CF 800 | B | complete | no consecutive 0 or 1 in the end | * |
| CF 800 | A | complete | alternate 1 and 0 | * |
| CF 799 | H | complete | maintain minimum prefix sum | ** |
| CF 786 | G | complete | find longest path after deleting edges must be deleted | *** |
| CF Edu_127 | E | complete | dp on tree, find lexicongraphically smallest possible string and compare | *** |
| CF 130 | D | complete | binary search for first position repeated, if no repeat, query 1 | *** |
| CF 130 | C | complete | delete b first, check all relative position of a and c | ** |
| CF 130 | B | complete | prefix sum | * |
| CF 130 | A | complete | don't be dumb | * |
| CF Edu_86 | D | complete | binary search, sorting | ** |
| CF Edu_82 | D | complete | bitmask, greedily combine small bags | ** |
| CF 798 | D | complete | not lots of useful squares, answer to right minus one, left add one | ** |
| CF 798 | B | complete | swaping only adjacent | * |
| CF 798 | A | complete | sort and choose min | * |
| CF Edu_67 | E | complete | dp change root | *** |
| CF 797 | G | complete | segment tree, interval merging | ** |
| CF 797 | F | complete | simple cycle finding, lcm | ** |
| CF 797 | E | complete | mod, two pointer | ** |
| CF 797 | D | complete | prefix sum | * |
| CF 797 | C | complete | don't be dumb | * |
| CF 797 | B | complete | don't be dumb | * |
| CF 797 | A | complete | don't be dumb | * |
| CF 776 | E | complete | disgusting implementation | ** |
| CF 672 | C | complete | always optimal to choose local min and max | *** |
| CF 558 | C | complete | when simplifying lines, consider horizontal and vertical lines | ** |
| CF 550 | E | complete | big number addition, division | ** |
| Grakn Forces | D | complete | suffix maximum, get minimum y based on x | *** |
| CF 796 | E | complete | get l for all path, sort l, if l is added to answer, keep path, otherwise leave it | *** |
| CF 796 | D | complete | initial has nothing to do with added | ** |
| CF 796 | C | complete | check parity | ** |
| CF 796 | B | complete | easy parity | * |
| CF 796 | A | complete | easy bitmask | * |
| CF 795 | E | complete | dsu merge blue with blue, red with red, remove blue red cross over | *** |
| CF 795 | D | complete | monotonic stack, prefix sum, segtree | *** |
| CF 795 | C | complete | decrease by either 1 or 10, make sure check causes with one 1, or no 1 | ** |
| CF 795 | B | complete | no single element | * |
| CF 795 | A | complete | odd even | * |
| CF 713 | C | complete | slope trick, minus i to compute non strictly increasing | *** |
| CF 13 | C | complete | slope trick | *** |
| CF Edu_129 | F | complete | dfs order, interval update, for all colors get size of separate components | *** |
| CF Edu_129 | C | complete | sort two first, do swap sort to generate swap | ** |
| CF Edu_129 | B | complete | just +b and mod | * |
| CF Edu_129 | A | complete | don't be stupid | * |
| CF 260 | A | complete | dp | ** |
| CF 793 | D | complete | find a root so that next one is 1, connect with previous or root | *** |
| CF 793 | C | complete | largest number with only one occurance can be made into two occurances | *** |
| CF 793 | B | complete | find all not equal position, & all of them | ** |
| CF 793 | A | complete | check same character in the middle | * |
| CF Edu_128 | E | complete | dp | *** |
| CF 792 | E | complete | greedy | *** |
| CF 792 | D | complete | the k(k-1)/2 is the same for all cases and don't matter when comparing | *** |
| CF 791 | C | complete | fenwick, rook not bishop I am terrible at chess | * |
| CF 791 | D | complete | binary search, tarjan find cycle | *** |
| CF 789 | E | complete | alternate for cycles | *** |
| CF 789 | D | complete | build row answer on the mth last row | *** |
| CF 789 | C | complete | prefix sum | ** |
| CF 789 | B2 | complete | greedy | ** |
| CF 789 | B1 | complete | implementation | * |
| CF 789 | A | complete | implementation | * |
| CF 788 | D | complete | precompute, answer add by 2 each time a new line cross an old line | *** |
| CF 788 | C | complete | do cycle with dsu, remove cycle that are locked by d | *** |
| CF 788 | B | complete | largest interval without special characters | ** |
| CF 788 | A | complete | move all negative to the front | * |
| CF 787 | F | complete | find path from x to y, brute force subtrees | ** |
| CF 787 | E | complete | dsu the letters | * |
| CF 786 | F | complete | maintain last point | ** |
| CF 785 | D | complete | check 0, -1, as long as ends don't touch, and lcm(d, q) == r | *** |
| CF 785 | C | complete | easy knapsack | * |
| CF 785 | B | complete | find last occurance of the letter, see if any letter not in the interval | ** |
| CF 785 | A | complete | type faster | * |
| CF 783 | D | complete | max fenwick, dp, only good making positive segment long, other segment can stay as size 1 | *** |
| CF 783 | C | complete | enumerate 0 position, brute force | ** |
| CF 783 | B | complete | sorting, implementation | * |
| CF 783 | A | complete | easy math | * |
| CF 782 | E | complete | dsu, if answer 0 -> common bit, if answer 1 -> common bit other than 1 before even edge, else answer 2, super node | *** |
| CF 782 | D | complete | calculate number of 1s, fenwick | *** |
| CF 782 | C | complete | math, prefix sum, greedy | ** |
| CF 782 | B | complete | if odd, make a move to first 1, otherwise turn first 2 0s to 1s | ** |
| CF 782 | A | complete | just brute force, don't try to be smart | * |
| CF Edu_126 | D | complete | fenwick store difference, increase by the largest first | *** |
| CF Edu_126 | C | complete | binary search | *** |
| CF Edu_126 | B | complete | precompute answers | ** |
| CF Edu_126 | A | complete | put all small number to one | * |
| CF 780 | F2 | complete | pigeonhole ignore adjacent, fenwick tree | *** |
| CF 780 | F1 | complete | easy enumeration | ** |
| CF 780 | D | complete | each separate by 0, delete left and right most negative is count is odd | * |
| CF Edu_125 | D | complete | dp, combine D and H | *** |
| CF Edu_125 | C | complete | regular can only be length 2, rest are all palindrome | ** |
| CF Edu_125 | B | complete | implementation | * |
| CF Edu_125 | A | complete | "Cause first move x second move y"(Leo Liu) | * |
| CF 777 | E | complete | binary lifting, greedy | **** |
| CF 777 | D | complete | multiple cases | *** |
| CF 777 | C | complete | greedy | ** |
| CF 777 | B | complete | check for whole rectangle | ** |
| CF 777 | A | complete | only 2 1 are possible | * |
| CF 772 | F | complete | big brain proof, fenwick tree, sort according to r | **** |
| CF 772 | E | complete | topological sort, dfs | **** |
| CF 772 | D | complete | dp, bitmask | *** |
| CF 772 | C | complete | greedy | ** |
| CF 772 | B | complete | greedy | ** |
| CF 772 | A | complete | bitmask | ** |
| CF 771 | D | complete | bfs | *** |
| CF 771 | C | complete | dsu, greedy, heap | ** |
| CF 771 | B | complete | sort parody | * |
| CF 771 | A | complete | greedy | * |
| CF 770 | D | complete | interactive | ** |
| CF 700 | C | complete | greedy | ** |
| CF 770 | B | complete | since guaranteed possible, focus on parity | *** |
| CF 770 | A | complete | check if palindrome | * |
| CF 769 | D | complete | segtree, binary search | *** |
| CF 764 | G | complete | bitmask, go from high bit, dsu, mst | *** |
| CF 764 | F | complete | interactive | *** |
| CF 764 | E | complete | dp | ** |
| Hello 2022 | C | complete | interactive, dfs | ** |
| Hello 2022 | B | complete | greedy, farthest segment | * |
| Hello 2022 | A | complete | greedy | * |
| CF Deltix Autumn21 | E | complete | obtain states, and costs to go to other states, maintain states with segtree | **** |
| CF Deltix Autumn21 | D | complete | brute force to store the state before arranging any non necessary moves | ** |
| CF Deltix Autumn21 | C | complete | dsu, merge consecutive 1s | * |
| CF Deltix Autumn21 | B | complete | just count how many abc are there | * |
| CF Deltix Autumn21 | A | complete | very simple greedy | * |
| CF 756 | F | complete | two pointer | *** |
| CF 756 | E2 | complete | dp, think of how one branch can protect the other | *** |
| CF 756 | E1 | complete | use BFS not DFS | ** |
| CF 756 | D | complete | basic tree dp | ** |
| CF 756 | C | complete | big scam, biggest value forces you to always choose other side | *** |
| CF 756 | B | complete | get better at math | * |
| CF 756 | A | complete | answer can only be -1, 1, 2 | * |
| CF 105 | D | complete | probability dp | *** |
| CF 399 | D | complete | probability dp | *** |
| CF 752 | C | complete | check the prefix | ** |
| CF 752 | B | complete | greedy, separate all into n, or n - 1 subsets | * |
| CF 752 | A | complete | implementation | * |
| CF Edu_44 | F | complete | hash all character | *** |
| CF Edu_2 | E | complete | save the result of heavy node, brute force light nodes | **** |
| CF Edu_65 | F | complete | when merging l and r, it is l[i] * (n - i + 1) + r[i] * i | **** |
| CF 748 | G | complete | segment tree interval merging, when fully cancel, the only remainings options are alternating brackets | **** |
| CF 748 | E | complete | bfs, priority queue, use multiset to lower time complexity | *** |
| CF 748 | D1 | complete | get difference, and get gcd | *** |
| CF 748 | C | complete | binary search | ** |
| CF 748 | B | complete | only consider two digits | * |
| CF 748 | A | complete | implmentation | * |
| CF Edu 115 | E | complete | dp[i][j][0/1] means ith row, jth column, coming from above or left | *** |
| CF Edu 115 | D | complete | find the number of cases that don't work, subtract from total | **** |
| CF Edu 115 | C | complete | um TLEed, should use map | *** |
| CF Edu 115 | B | complete | simple implementation | ** |
| CF Edu 115 | A | complete | simple observation | * |
| CF 747 | E1 | complete | combinatorics | * |
| CF 747 | D | complete | dsu, mark all subsets, get the sum of the maximum possible subsets | *** |
| CF 747 | C | complete | mark all factors, answer can only be 0 1 or 2 | *** |
| CF 747 | B | complete | bitmask, fast_pow | ** |
| CF 747 | A | complete | two numbers always work are n and -(n - 1) | * |
| CF 746 | D | complete | binary search, answer is maximum edge, euler tour | *** |
| CF 746 | C | complete | Separate into case odd and even, only really need 1 or 2 edges deleted | *** |
| CF 746 | B | complete | if one is not at the prooper position and it is stuck, answer is NO | ** |
| CF 746 | A | complete | don't use loop, just use math | * |
| CF global 15 | F | complete | all portals after current must be on, fenwick tree | *** |
| CF 744 | G | complete | use relative position to the l endpoint to avoid negative index | **** |
| CF 744 | F | complete | dfs on zeros, build graph | *** |
| CF 744 | E2 | complete | fenwick tree or balanced data structure, greedy | *** |
| CF 744 | E1 | complete | simulate | * |
| CF 744 | D | complete | do meeting one by one greedy, don't just subtract | ** |
| CF 744 | C | complete | brute force | * |
| CF 744 | B | complete | reverse when sorting | * |
| CF 744 | A | complete | count A, B, C | * |
| CF Edu 114 | D | complete | priority queue to search max, hash banned, make sure add vis | **** |
| CF Edu 114 | C | complete | binary search for hero to send | *** |
| CF Edu 114 | B | complete | annoying math | ** |
| CF Edu 114 | A | complete | dfs | * |
| CF 743(div 2) | C | complete | cycle detection, see if it is DAG, then do dp | **** |
| CF 743(div 2) | B | complete | make A or B monotone, then Binary Search | ** |
| CF 743(div 2) | A | complete | move all numbers to the right and then subtract, greedy | * |
| Global 16 | E | complete | separate all component, merge them, order don't matter, no global variable | **** |
| Global 16 | D | complete | greedy, fenwick | *** |
| Global 16 | C | complete | greedy | ** |
| Global 16 | B | complete | greedy | * |
| Global 16 | A | complete | greedy | * |
| CF Edu_113 | D | complete | only both on x or y, binary search, enumerate people add to time not multiply | *** |
| CF Edu_113 | C | complete | case by case, for all permutations, k out of k + 1 of them work | **** |
| CF 742 | E | complete | interval merging segment tree | **** |
| CF 742 | D | complete | greedy, go from highest digit to the lowest digit | **** |
| CF 742 | C | complete | big brain observation | **** |
| CF 742 | B | complete | working with xor, xor properties | ** |
| CF 742 | A | complete | switching U with D and vice versa | * |
| CF Deltix21 | E | complete | turn it into bracket pairing, sparse table | **** |
| CF Deltix21 | D | complete | interactive, get numbers three a time, (a & b) + (a ｜ b) == a + b | **** |
| CF Deltix21 | C | complete | implementation, details very important | *** |
| CF Deltix21 | B | complete | odd even, moving numbers | *** |
| CF Deltix21 | A | complete | straight forward | * |
| CF 741 | E | complete | dp, longest prefix substring, only if the first different character is different | ***** |
| CF 741 | D2 | complete | map, binary search for position, prefix sum | **** |
| CF 741 | D1 | complete | separate into odd even, prefix sum | **** |
| CF 741 | C | complete | case by case | **** |
| CF 741 | B | complete | case by case | *** |
| CF 741 | A | complete | pick r / 2 + 1, or l | ** |
| CF 740(div 2) | D2 | complete | suffix-sum, dp, two cases | **** |
| CF 740(div 2) | D1 | complete | any range data structure, dp, two cases | **** |
| CF 740(div 2) | C | complete | turn each cave into a node, sorting | *** |
| CF 740(div 2) | B | complete | brute force, math | ** |
| CF 740(div 2) | A | complete | implementation | ** |
| CF 739 | F2 | complete | greedy, enumerate digits, using multiset and pointers to make it easier | **** |
| CF 739 | F1 | complete | precomplete, binary search | *** |
| CF 739 | E | complete | first get second answer, then compute first, then check | *** |
| CF 739 | D | complete | bit by bit | ** |
| CF 739 | C | complete | math, logics | * |
| CF 739 | B | complete | math | * |
| CF 739 | A | complete | implementation | * |
| CF 738 | D2 | complete | DSU, try random nodes from random components from the two forests until we have enough edges | ***** |
| CF 738 | D1 | complete | disjoint set union on two forests | ** |
| CF 738 | C | complete | just try to insert the n + 1 node into any interval | * |
| CF 738 | B | complete | greedy, just ulternate B and R | * |
| CF 738 | A | complete | minimum of all is to &(and) all numbers | * |
| CF 737 | C | complete | Fermat's Little Theorem, fast_pow, careful of integer overflow, case by case, working with bit | **** |
| CF 737 | B | complete | greedy, sorting, binary search | *** |
| CF 737 | A | complete | greedy, setprecision | ** |
| CF 736 | C | complete | greedy | *** |
| CF 734 | E | complete | big brain dp | **** |
| CF 734 | C | complete | sorting | ** |
| CF Edu_112 | E | complete | Segment Tree using minimum to check segments, two pointer | **** |
| CF Edu_112 | D | complete | Prefix Sum & enumeration | ** |
| CF Edu_112 | C | complete | Prefix Sum & greedy | ** |
| CF Edu_112 | B | complete | too dumb, consider cases and enumeration | ** |
| CF Edu_112 | A | complete | Greedy | ** |
| CF 732 Div 2 | C | complete | separate position to even and odd | *** |
| CF 732 Div 2 | B | complete | store the postion for each letter | ** |
| CF 728 Div 2 | C | complete | greedy, sorting, implementation | *** |
| CF 728 Div 2 | B | complete | greedy, enumeration | ** |
| CF 728 Div 2 | A | complete | greedy | * |
| CF 727 | D | complete | greedy, kind of discretization | *** |
| CF 727 | C | complete | greedy, binary search | *** |
| CF 727 | B | complete | prefix sum with alphabet | ** |
| CF 727 | A | complete | implementation | ** |
| CF Edu_110 | C | complete | two pointer | **** |
| CF Edu_110 | B | complete | sort into first even, then odd | *** |
| CF LATOKEN | F2 | complete | Tarjan, Greedy(Gassing Bonny), dp on DAG | ***** |
| CF LATOKEN | F1 | complete | Tarjan, find all with in degree 0 | **** |
| CF LATOKEN | D | complete | bipartite characteristics of trees | *** |
| CF LATOKEN | C | complete | Realize cycle find numbers of cycle | ** |
| CF LATOKEN | B | complete | decrease only when one single column is tall | ** |
| CF 725 | G | complete | Binary Search, inequalities | **** |
| CF 725 | F | complete | number theory, each digit changed r - l times | ** |
| CF 725 | E | complete | implementation, STL | *** |
| CF 725 | D | complete | number theory, calculate prime numbers beforehand | *** |
| CF 725 | C | complete | binary Search | ** |
| CF 724 | D | complete | binary Search, Set | |
| CF 724 | C | complete | dynamic programming, pattern | *** |
| CF 724 | B | complete | enumerating string properly | ** |
| CF 724 | A | complete | analyze the problem to find out pattern on the sample test case | * |
| CF 520 | Company | incomplete | LCA, segment tree/sparse tree | ***** |
| CF 713 | Education | complete | enumeration, not greedy | *** |
| CF 713 | Permutation by Sum | complete | Greedy, enumerate one by one | *** |
| CF 713 | Short Task | complete | Calculate beforehand, number theory | *** |
| CF 708 | K LCM | complete | greedy, let all other numbers be 1 only consider the last three | *** |
| CF 702 | Old Floppy Drive | complete | Prefix Sum, binarySearch, replace with Maximum | **** |
| CF 702 | Advertising Agency | complete | Math, Fermat's little theorem | ** |
| CF 697 | Accidental Victory | complete | Binary Search, sorting | *** |
| CF 697 | Cleaning the Phone | complete | Sorting, Binary Search | *** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| c4 | J4 | complete | binary lifting | ** |
| c4 | P5 | complete | do all q2, then binary search q1, and then sort | *** |
| c4 | P4 | complete | sparse table, binary search | ** |
| c4 | P3 | complete | ternary search | * |
| c4 | P2 | complete | dfs | * |
| c4 | P1 | complete | implementation | * |
| c3 | P5 | complete | string hashing | ** |
| c3 | P4 | complete | do in reverse order, dsu, lca | *** |
| c3 | P3 | complete | customized sorting | ** |
| c3 | P2 | complete | binary search | ** |
| c3 | P1 | complete | don't be stupid | * |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| Hard | Median of Two Sorted Arrays | complete | priority queue one small one big | ** |
| Source | Problems | status | skills needed | rating |
|---|---|---|---|---|
| braziloi 19 | P2 | complete | graph theory | *** |
| JOI 17 | P4 | complete | dijkstra | *** |
| COCI 07 c6 | P5 | complete | array of sets, cheesed with clearing map | ** |
| DMOJ | wac1p4 | complete | tree dp | *** |
| DMOJ | cpc21c1p6 | complete | sort A, do segtree on B and C | *** |
| COCI 22 c4 | P2 | complete | dp | *** |
| Japan OI | joi13op3 | complete | binary search, dynamic programming, 2 pointer | ** |
| Baltic OI | btoi05p5 | complete | dp, priority queue | *** |
| COCI 22 c4 | P5 | complete | segtree | ** |
| Baltic OI | btoi18p6 | complete | math, case by case | ** |
| CEOI 17 | ceoi17p4 | complete | li chao tree, convex hull trick | *** |
| Baltic OI | btoi17p2 | complete | matrices segtree | *** |
| DMOJ | wc99sp6 | complete | priority_queue | *** |
| APIO 12 | P1 | complete | dsu on tree | *** |
| COCI 07 c3 | P6 | complete | array in segtree | ** |
| DMOJ | cheapsegments | complete | sort l, put r into segtree | ** |
| COCI 19 c6 | P5 | complete | hash, don't dare using aho korasick | *** |
| COCI 07 c1 | P5 | complete | count big and small | * |
| SHOI 2012 | 回家的路 | complete | layered graph | ** |
| POI | TEL-Teleportation | complete | layered graph | *** |
| NA | 孤岛营救问题 | complete | layered graph for all possible key combinations | *** |
| JLOI2011 | 飞行路线 | complete | layered graph | ** |
| Atcoder DP | T | cmoplete | psa | *** |
| DMOJ | invperm | complete | swap first with last, do a cyclic shift | ** |
| DMOJ | Traffic Light | complete | shortest path | ** |
| COCI 22 c1 | P5 | complete | enumerate r, find l, only logMax possible l | *** |
| COCI 13 c5 | P3 | complete | hash, stack | * |
| CEOI 18 | P2 | complete | find LIS from front and back, try to combine them | ** |
| COCI 16 c7 | P4 | complete | maintain ending 0s | ** |
| DMOJ | wac3p5 | complete | dp, psa | ** |
| DMOJ | acmtryouts1e | complete | dp, psa | ** |
| DMOJ | acc3p4 | complete | two segtree, interval update i * a[i] value | *** |
| COCI 17 | P4 | complete | divid by 2 to brute force, use pbds | *** |
| DMOJ | lemontree | complete | centroid decomposition, minus M at the beginning | *** |
| JOI 22 Final | P2 | complete | bs answer | ** |
| DMPG 19 | G5 | complete | centroid decomposition, LCA, lazy | *** |
| CEOI 09 | Harbingers | complete | dp, convex hull trick, ternary search, maintain previous stack | **** |
| Atcoder DP | S | complete | digit dp | ** |
| Atcoder DP | R | complete | matrices | ** |
| Atcoder DP | Q | complete | segtree | ** |
| Atcoder DP | M | complete | prefix sum, dp | ** |
| DMOJ | revdig | complete | easy application of max flow | ** |
| utso15 | utso15p5 | complete | kruskal, LCA | ** |
| DMOJ | seed5 | complete | minimum cut | *** |
| DMOJ | bts18p6 | complete | math, difference array | *** |
| DMOJ | Monkey Motel | complete | segtree, dfs order | *** |
| Atcoder | coins | complete | probability dp | ** |
| DMOJ | btoi09p2 | complete | same as victor rain | *** |
| DMOJ | higgs | complete | easy segtree | * |
| DMOJ | A plus B hard | complete | high precision | ** |
| SAC 22 c5 | P4 | complete | merge interval with two pointer | ** |
| DMOJ | Lexicographically Least Substring | complete | skip already matched, brute force check last position | ** |
| CTU Open 2018 | Escalator | complete | bit by bit, dsu | ** |
| apio 2007 | Mobiles | complete | tree dp, read problem carefully | ** |
| wlxsq | 合并果树 | complete | sort using frequency array, coordinate compression | *** |
| Facebook Hacker Cup '15 Round 1 | Homework | complete | seive and add 1 to cnt every time seiving | ** |
| 第k小值 | complete | bs, two pointer | *** | |
| DMOJ | Tenri | complete | bitmask dp | ** |
| wlxsq | 相遇 | complete | LCA | *** |
| wlxsq | 包裹传递 | complete | bs, same three decimal places | ** |
| DMOJ | Lemon Game | complete | game theory, euclidean alg | ** |
| DMOJ | comparing arrays | complete | hash on segtree | ** |
| DMOJ | hydration | complete | bs for answer | ** |
| DMOJ | Chirstmas Cards | complete | knapsack | ** |
| TJOI | 猜数字 | complete | chinese remainder theorem, fast multiply | *** |
| DMOJ | N-Kat | complete | the minimum two sets where not completely contained which have best answer is the answer | *** |
| DMOJ | balancing act | complete | easy dfs | * |
| atcoder | deque | complete | game theory dp | * |
| dmoj | Levves Loves Segment Tree | complete | dynamic segment tree | ** |
| dmoj | 2 Primes | complete | prime sieving | *** |
| dmoj | Dog Girls | complete | kmp, string hashing | *** |
| HDU | Gorgeous Sequence | complete | segment tree, update to min | *** |
| COCI 14c5 | P4 | complete | implementation | ** |
| dmoj | String Finding | complete | string hashing | * |
| wlxsq | 士兵占领 | complete | dinic | *** |
| JSOI | blue mary | complete | li chao tree | *** |
| NOI Online | 丹钓战 | complete | fenwick tree, monotonic stack | *** |
| wlxsq | 运输问题 | complete | max flow minimum cost, dinic, EK | ** |
| wlxsq | 分配问题 | complete | max flow minimum cost, dinic, EK | ** |
| wlxsq | 方格取数 | complete | max flow, bipartite graph | *** |
| TLE 16 c8 | P5 | complete | max flow/bipartite | *** |
| ICPC | knapsack 4 | complete | dp store difference, random shuffle | *** |
| DMOJ | Kth-Rank Student | complete | pbds ordered set, merge light into heavy | *** |
| wlxsq | 可达性统计 | complete | bitset | *** |
| DMOJ | Fox Girls | complete | every connected component is tree plus an edge, run tree dp | **** |
| DMOJ | Boxling | complete | fenwick, linesweep | *** |
| DMOJ | Farming Simulator | complete | dp | *** |
| wlxsq | 星球大战 | complete | compute in reverse order | *** |
| COCI | Bicikli | complete | tarjan scc, dp | *** |
| DMOJ | Inaho IX | complete | matrices multiplication | **** |
| DMOJ | Training Regimen | complete | dsu | *** |
| DMOJ | Multiplication Madness | Fermat's little theorem | * | |
| NA | 绝对价值 | complete | DSU | ** |
| Atcoder | Knapsack 2 | complete | reverse weight and value | ** |
| DMOJ | A Subarray Problem | complete | dsu or keep upper and lower bound | ** |
| DMOJ | City Game | complete | monotonic stack, find top and bottom bounds for a maximum length at a position | *** |
| COCI | Index | complete | Mo's Algorithm, segment tree | *** |
| DMOJ | Serial Killer | complete | segment tree, dp | ** |
| DMOJ | A Rage Tree Problem | complete | segment tree, lazy propagation | *** |
| DMOJ | Fax's Christmas Bash | complete | fenwick tree to store coefficients, binary search for convex, use ceiling or floor | **** |
| DMOJ | Good Debugging | complete | segment tree, lazy propagation | ** |
| NA | 逆序对 | complete | Mo's Algorithm, fenwick tree | *** |
| NA | 温度测量 | complete | segment tree, maintain lowest temperature possible starting from some point before | *** |
| NOI | Travel | complete | dp on DAG | ** |
| CSP S | 廊桥分配 | complete | greedy | *** |
| DMOJ | check number | complete | binary search | ** |
| DMOJ | Arithmetic Snowman | complete | dp, be careful of memory | ** |
| DMOJ | nightmare-a-thon | complete | segment tree | ** |
| DMOJ | knapsack 3 | complete | knapsack binary packaging | *** |
| NOIP 18 | Paving Road | complete | very standard dp | * |
| DMOJ | Mimi and Division | complete | partition algorithm & brute force | *** |
| DMOJ | Frog 3 | complete | Convex Hull Trick | **** |
| UCC | WoodCutting Game | complete | game theory dp | *** |
| DMOJ | pick up | complete | dp | ** |
| COCI 16 c4 | kas | complete | dp stores difference between two numbers | *** |
| DMOJ | Cheapest Operation Ever | complete | Convex Hull Trick dp | **** |
| CSP S 21 | 回文 | complete | big brain observation | *** |
| APIO 14 | Split the Sequence | complete | Convex Hull Trick dp | **** |
| NA | 最长异或路径 | complete | Trie | *** |
| JSOI 2012 | 玄武密码 | complete | AC automaton | **** |
| DMOJ | Victor Makes Banks | complete | matrices power, consider case when n = 1 | *** |
| DMOJ | 最小逆序对数 | complete | very standard fenwick tree | ** |
| DMOJ | School Traversal | complete | very easy and standard lca | * |
| DMOJ SAC | That Problem | complete | dp, memory optimization | ** |
| DMOJ SAC | That Wall | complete | binary search, dp | *** |
| DMOJ | Poutine | complete | lca, mantain max and second max | ** |
| DMOJ | GGG | complete | change the index of the first array, LIS | ** |
| DMOJ | Bruce's Little Bridge | complete | merge nodes together that don't have edge length 1 | *** |
| DMOJ | Joey and Biology | complete | shortest editing distance | ** |
| DMOJ | Holy Grail War | complete | interval merging segment tree | *** |
| DMOJ | Strict Evaluation | complete | basic lazy propagation | *** |
| DMOJ | Subway_Routes | complete | locate the middle of the perimeter, and then dfs there | **** |
| NOI 21 | P1 | complete | heavy light decomposition, set heavy edges as that two of the nodes have the same value, update different value every time | ****** |
| SDOI | 染色 | complete | combining intervals, heavy light decomposition | **** |
| DMOJ | figurine | complete | lazy propagation, keep max for A and B, {maxA, k}, {k, maxB} | **** |
| NA | 树上操作 | complete | heavy light decomposition | *** |
| NA | 最小生成树? | complete | shrink LCA(not yet implemented) | *** |
| DMOJ | Maria and Maze | complete | don't binary search | ** |
| NA | 最大生成森林 | complete | dsu, binary search | *** |
| SCOI | 游戏 | complete | knapsack dp, sum to n, find number of unique LCM | **** |
| DMOJ | 2spooky4me | complete | discretization, lazy | *** |
| DMOJ | redstone | if a node you can visit is incycle add one to amount of cycles | ** | |
| NA | JM挑数 | complete | multiset | ** |
| NA | dynamic median | complete | priority queue, one for small one for big | *** |
| NOIP 2017 | D2T3 | 列队 | complete | splay tree |
| NA | Interval Reversal | complete | splay tree | ***** |
| Another Contest 8 | P5 | complete | fenwick to find number of sequences | *** |
| Another Contest 8 | P3 | complete | find a cycle | *** |
| NA | 网络分析 | complete | dsu, dp | ** |
| NOI 2009 | Modified Treap | complete | interval dp, let w be best answer with root weight >= w, discretization, sorting | **** |
| NA | 部落战争 | complete | bipartite matching | *** |
| CTSC 2000 | 邱比特的烦恼 | complete | KM algorithm, math | **** |
| DMOJ | Persuation | complete | bitmask, 0x3f3f3f3f was not big enough | *** |
| DMOJ | BST test | complete | treap | **** |
| DMOJ | dynamic sum | complete | binary search, segment tree/block matrix too slow | *** |
| DMOj | K-th Minimum Number | complete | merge sort segment tree | ***** |
| CSP-S | 能量项链 | complete | interval dynamic programming | *** |
| LOJ | 家庭作业 | complete | heap, greedy, segment tree or disjoint set union | **** |
| TJOI | 攻击装置 | complete | bipartite matching, tile coloring | **** |
| NA | 合唱团 | complete | dp, 1 for place at beginning, n for placing at the end | **** |
| CPC | P4 | complete | reverse graph I am so dumbbbb | ** |
| CPC | P1 | complete | turn B into 2a * 5b | ** |
| NA | 最小弹药数 | complete | bipartite matching | *** |
| VM7WC | Uniting the Earth Empire | complete | Montone stack | ** |
| NA | 棋盘覆盖 | complete | hungarian algorithm bipartite matching | **** |
| SCOI | 糖果 | complete | 差分约束 | *** |
| ACM | The Great ATM Robbery | complete | Tarjan | **** |
| Bulgarian OI 09 | P4 | complete | Monotone Stack | ** |
| COI | Patrik | complete | Monotone Stack | ** |
| NA | 树上差分 | complete | LCA, Segment Tree, lazy on tree | **** |
| DMPG | Black and White | complete | two dimensional lazy | ** |
| DMOJ | Subtree | complete | DP on trees, switch the root, pre-suf sum to avoid modular inverse when MOD is not prime | |
| NA | 钓鱼 | complete | dynamic programming | ** |
| ACM | 数列第n项 | complete | matrices, factoring | *** |
| UTS Open 21 | State Taxes | complete | block_mat, segment tree | **** |
| UTS Open 21 | Latin Class | complete | dynamic programming, prefix-sum | ** |
| UTS Open 21 | Prime Arrays | complete | Big Brain Greedy | ** |
| DMOJ | Fibonacci hard | complete | Matrices, store big numbers as string, fast_pow in base 10 to avoid dividing strings | ***** |
| DMOJ | Fibonacci | complete | Matrices, fast_pow | ** |
| P3043 | 涂抹果酱 | complete | bitmasking, dynamic programming | **** |
| P3041 | TSP 问题 | complete | bitmasking, dynamic programming | *** |
| P0414 | 最小瓶颈路 | complete | lca | *** |
| P3042 | 炮兵阵地 | complete | bitmasking, dynamic programming | **** |
| P0511 | 状态压缩DP | complete | bitmasking dynamic programming | **** |
| P3036 | 树上最远点对 | complete | LCA, Segment Tree, property of diameter of the tree | *** |
| NA | 区间lca | complete | lca, segment tree/sparse table | **** |
| NA | 次小生成树 | complete | LCA, first getMax, then update x, y | **** |
| DMOJ | dynamic range minimum query | complete | Segment Tree | * |
| COCI | Zapis | complete | Dynamic Programming, iomanip | *** |
| COCI | Dostavljač | complete | Graph Theory, Dynamic Programming, knapsack problem | |
| DMOJ | Dominos Tiling | complete | Dynamic Programming, two cases | * |
| DMOJ | CamelCase | complete | Dynamic Programming, unordered_set | * |
| NA | 区间异或 | complete | Segment Tree, property of xor, writing number as an array in binary | *** |
| DMOJ | Cat Girls | complete | Dynamic Programming, Binary Search, this question is so wrong | * |
| NA | 小白逛公园 | complete | Segment Tree | ** |
| USACO | 旅馆预订 | complete | Segment Tree | **** |
| NA | 47序列 | complete | Segment Tree | **** |
| NA | 维护序列 | complete | Segment Tree, first multiply then addition | *** |
| NA | 区间操作 | complete | Segment Tree | ** |
| NA | 弱点 | complete | Segment Tree, compute segment tree twice | ** |
| NA | Interval GCD | complete | two Segment Tree, properties of GCD, be careful about absolute value | **** |
| CCF Online | 重力球 | incomplete | ||
| CCF Online | 吃豆人 | incomplete | Prefix Sum, enumeration, greedy | **** |
| CCF Online | 切蛋糕 | complete | case enumeration you need not more than three cuts | *** |
| NOIP | 魔法阵 | complete | enumeration | **** |
| CSP 2019 | 纪念品 | complete | knapsack problem, dynamic programming | **** |
| CSP 2019 | 加工零件 | complete | bfs, number theory | **** |