LeetCode
Up to date (2016-10-09), there are 401
Algorithms / 13
Database / 4
Shell questions on LeetCode Online Judge.
The number of questions is increasing recently.
Here is the classification of all 418
questions.
For more questions and solutions, you can see my LintCode repository.
I'll keep updating for full summary and better solutions. Stay tuned for updates.
(Notes: "
Algorithms
- Bit Manipulation
- Array
- String
- Linked List
- Stack
- Queue
- Heap
- Tree
- Hash Table
- Data Structure
- Math
- Two Pointers
- Sort
- Recursion
- Binary Search
- Binary Search Tree
- Breadth-First Search
- Depth-First Search
- Backtracking
- Dynamic Programming
- Greedy
- Design
Database
Shell
Bit Manipulation
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
136 | Single Number | C++ Python | O(n) | O(1) | Medium ||
137 | Single Number II | C++ Python | O(n) | O(1) | Medium ||
190 | Reverse Bits | C++ Python | O(1) | O(1) | Easy ||
191 |Number of 1 Bits | C++ Python | O(1) | O(1) | Easy ||
201 | Bitwise AND of Numbers Range | C++ Python | O(1) | O(1) | Medium ||
231 | Power of Two | C++ Python | O(1) | O(1) | Easy | LintCode |
260 | Single Number III | C++ Python | O(n) | O(1) | Medium ||
268| Missing Number | C++ Python | O(n) | O(1) | Medium | LintCode ||
318| Maximum Product of Word Lengths | C++ Python | O(n) ~ O(n^2) | O(n) | Medium || Bit Manipulation, Counting Sort, Pruning|
342 | Power of Four | C++ Python | O(1) | O(1) | Easy | |
371 | Sum of Two Integers | C++ Python | O(1) | O(1) | Easy | LintCode |
389 | Find the Difference | C++ Python | O(n) | O(1) | Easy | |
393 | UTF-8 Validation | C++ Python | O(n) | O(1) | Medium | |
401 | Binary Watch | C++ Python | O(1) | O(1) | Easy | |
411 | Minimum Unique Word Abbreviation | C++ Python | O(2^n) | O(n) | Hard |
Array
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
15 | 3 Sum | C++ Python | O(n^2) | O(1) | Medium || Two Pointers
16 | 3 Sum Closest | C++ Python | O(n^2) | O(1) | Medium || Two Pointers
18| 4 Sum | C++ Python | O(n^3) | O(1) | Medium || Two Pointers
26 | Remove Duplicates from Sorted Array| C++ Python | O(n) | O(1) | Easy || Two Pointers
27 | Remove Element | C++ Python | O(n) | O(1) | Easy ||
31 | Next Permutation| C++ Python | O(n) | O(1) | Medium || Tricky
41 | First Missing Positive| C++ Python | O(n) | O(1) | Hard || Tricky
48 | Rotate Image | C++ Python | O(n^2) | O(1) | Medium ||
54 | Spiral Matrix | C++ Python | O(m * n) | O(1) | Medium ||
59 | Spiral Matrix II | C++ Python | O(n^2) | O(1) | Medium ||
66 | Plus One | C++ Python | O(n) | O(1) | Easy ||
73 | Set Matrix Zeroes | C++ Python | O(m * n) | O(1) | Medium ||
80 | Remove Duplicates from Sorted Array II| C++ Python | O(n) | O(1) | Medium || Two Pointers
118 | Pascal's Triangle| C++ Python | O(n^2) | O(1) | Easy ||
119 | Pascal's Triangle II| C++ Python | O(n^2) | O(1) | Easy ||
121 | Best Time to Buy and Sell Stock| C++ Python | O(n) | O(1) | Medium ||
128 | Longest Consecutive Sequence| C++ Python | O(n) | O(n) | Hard || Tricky
157 | Read N Characters Given Read4 | C++ Python | O(n) | O(1) | Easy |
String
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
5| Longest Palindromic Substring | C++ Python | O(n) | O(n) | Medium || Manacher's Algorithm
6| ZigZag Conversion | C++ Python | O(n) | O(1) | Easy ||
8| String to Integer (atoi) | C++ Python | O(n) | O(1) | Easy ||
14| Longest Common Prefix | C++ Python | O(n * k) | O(1) | Easy ||
28| Implement strStr() | C++ Python | O(n + k) | O(k) | Easy || KMP Algorithm
38| Count and Say | C++ Python| O(n * 2^n) | O(2^n) | Easy ||
43| Multiply Strings | C++ Python | O(m * n) | O(m + n) | Medium ||
58| Length of Last Word | C++ Python | O(n) | O(1) | Easy ||
67| Add Binary | C++ Python | O(n) | O(1) | Easy ||
68| Text Justification | C++ Python | O(n) | O(1) | Hard ||
125| Valid Palindrome | C++ Python | O(n) | O(1) | Easy ||
151| Reverse Words in a String | C++ Python | O(n) | O(1) | Medium ||
161| One Edit Distance | C++ Python | O(m + n) | O(1) | Medium |KMP Algorithm
Manacher's Algorithm
242| Valid Anagram| C++ Python | O(n) | O(1) | Easy | LintCode |
271| Encode and Decode Strings | C++ Python | O(n) | O(1) | Medium |
Linked List
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
2| Add Two Numbers | C++ Python | O(n) | O(1) | Medium ||
21| Merge Two Sorted Lists| C++ Python | O(n) | O(1) | Easy ||
23| Merge k Sorted Lists | C++ Python | O(nlogk)| O(1)| Hard | | Heap, Divide and Conquer
24| Swap Nodes in Pairs| C++ Python | O(n) | O(1) | Medium ||
25| Reverse Nodes in k-Group| C++ Python | O(n) | O(1) | Hard ||
61| Rotate List| C++ Python | O(n) | O(1) | Medium ||
82| Remove Duplicates from Sorted List II| C++ Python | O(n) | O(1) | Medium ||
83| Remove Duplicates from Sorted List| C++ Python | O(n) | O(1) | Easy ||
92| Reverse Linked List II| C++ Python | O(n) | O(1) | Medium ||
138| Copy List with Random Pointer | C++ Python | O(n) | O(1) | Hard ||
160| Intersection of Two Linked Lists| C++ Python | O(m + n) | O(1) | Easy ||
203| Remove Linked List Elements| C++ Python | O(n) | O(1) | Easy ||
206| Reverse Linked List| C++ Python | O(n) | O(1) | Easy ||
234| Palindrome Linked List| C++ Python | O(n) | O(1) | Easy ||
237| Delete Node in a Linked List| C++ Python | O(1) | O(1) | Easy | LintCode |
328| Odd Even Linked List| C++ Python | O(n) | O(1) | Easy | |
369| Plus One Linked List| C++ Python | O(n) | O(1) | Medium |
Stack
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
20| Valid Parentheses| C++ Python | O(n) | O(n) | Easy ||
32| Longest Valid Parentheses| C++ Python | O(n) | O(1) | Hard ||
71| Simplify Path| C++ Python | O(n) | O(n) | Medium ||
84| Largest Rectangle in Histogram | C++ Python | O(n) | O(n) | Hard || Ascending Stack, DP
85| Maximal Rectangle| C++ Python| O(m * n) | O(n) | Hard | EPI | Ascending Stack
101| Symmetric Tree| C++ Python | O(n) | O(h) | Easy ||
150| Evaluate Reverse Polish Notation| C++ Python| O(n)| O(n)| Medium ||
155| Min Stack | C++ Python | O(n) | O(1) | Easy ||
173| Binary Search Tree Iterator | C++ Python | O(1)| O(h)| Medium ||
224| Basic Calculator | C++ Python | O(n)| O(n)| Medium ||
227| Basic Calculator II | C++ Python | O(n)| O(n)| Medium ||
232| Implement Queue using Stacks | C++ Python | O(1), amortized| O(n)| Easy | EPI, LintCode |
255| Verify Preorder Sequence in Binary Search Tree | C++ Python | O(n)| O(1)| Medium |
Queue
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
239| Sliding Window Maximum| C++ Python | O(n) | O(k) | Hard | EPI, LintCode |
281| Zigzag Iterator| C++ Python | O(n) | O(k) | Medium |
Heap
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
264| Ugly Number II | C++ Python | O(n) | O(1) | Medium | CTCI, LintCode | BST, Heap |
295| Find Median from Data Stream | C++ Python | O(nlogn) | O(n) | Hard | EPI, LintCode | BST, Heap |
313| Super Ugly Number | C++ Python | O(n * k) | O(n + k) | Medium || BST, Heap |
358| Rearrange String k Distance Apart| C++ Python | O(n) | O(n) | Hard |
Tree
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
94 | Binary Tree Inorder Traversal | C++ Python | O(n)| O(1)| Medium || Morris Traversal
|
99 | Recover Binary Search Tree | C++ Python | O(n)| O(1)| Hard || Morris Traversal
144 | Binary Tree Preorder Traversal | C++ Python | O(n)| O(1)| Medium || Morris Traversal
145 | Binary Tree Postorder Traversal | C++ Python | O(n)| O(1)| Hard || Morris Traversal
208 | Implement Trie (Prefix Tree) | C++ Python | O(n) | O(1) | Medium || Trie
211 | Add and Search Word - Data structure design | C++ Python | O(min(n, h)) | O(min(n, h)) | Medium || Trie, DFS
226| Invert Binary Tree | C++ Python | O(n) | O(h), O(w) | Easy ||
297 | Serialize and Deserialize Binary Tree | C++ Python | O(n) | O(h) | Medium | LintCode | DFS
307 | Range Sum Query - Mutable | C++ Python | ctor: O(n), update: O(logn), query: O(logn) | O(n) | Medium | LintCode | DFS, Segment Tree, BIT
308 | Range Sum Query 2D - Mutable | C++ Python | ctor: O(m * n), update: O(logm + logn), query: O(logm + logn) | O(m * n) | Hard |
Hash Table
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
1| Two Sum | C++ Python | O(n) | O(n) | Easy ||
3| Longest Substring Without Repeating Characters | C++ Python | O(n) | O(1) | Medium ||
30| Substring with Concatenation of All Words | C++ Python | O(m * n * k) | O(n * k) | Hard ||
36| Valid Sudoku | C++ Python | O(9^2) | O(9) | Easy ||
49| Group Anagrams | C++ Python | O(n * glogg) | O(n) | Medium ||
76| Minimum Window Substring | C++ Python | O(n) | O(k) | Hard ||
149| Max Points on a Line | C++ Python | O(n^2) | O(n) | Hard ||
159| Longest Substring with At Most Two Distinct Characters| C++ Python | O(n) | O(1) | Hard |
Data Structure
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| ----- 146| LRU Cache | C++ Python | O(1) | O(k) | Hard || 225| Implement Stack using Queues | C++ Python | push: O(n), pop: O(1), top: O(1) | O(n) | Medium ||
Math
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
7| Reverse Integer | C++ Python | O(1) | O(1) | Easy ||
9| Palindrome Number | C++ Python | O(1) | O(1) | Easy ||
12| Integer to Roman | C++ Python | O(n) | O(1) | Medium ||
13| Roman to Integer | C++ Python | O(n) | O(1) | Easy ||
29| Divide Two Integers | C++ Python | O(1) | O(1) | Medium ||
50| Pow(x, n) | C++ Python | O(1) | O(1) | Medium ||
60| Permutation Sequence | C++ Python | O(n^2) | O(n) | Medium || Cantor Ordering
65| Valid Number | C++ Python | O(n) | O(1) | Hard || Automata
89| Gray Code | C++ Python | O(2^n) | O(1) | Medium ||
166| Fraction to Recurring Decimal | C++ Python | O(logn) | O(1) | Medium ||
168| Excel Sheet Column Title | C++ Python | O(logn) | O(1) | Easy ||
171| Excel Sheet Column Number | C++ Python | O(n) | O(1) | Easy ||
172| Factorial Trailing Zeroes | C++ Python | O(1) | O(1) | Easy ||
223| Rectangle Area | C++ Python | O(1) | O(1) | Easy ||
233| Number of Digit One | C++ Python | O(1) | O(1) | Medium | CTCI, LintCode|
248| Strobogrammatic Number III | C++ Python | O(5^(n/2)) | O(n) | Hard |Reservoir Sampling
|
386 | Lexicographical Numbers | C++ Python | O(n) | O(1) | Medium |||
390 | Elimination Game | C++ Python | O(logn) | O(1) | Medium ||
391 | Perfect Rectangle | C++ Python | O(n) | O(n) | Hard | |
398 | Random Pick Index | C++ Python | O(n) | O(1) | Medium || Reservoir Sampling
|
400 | Nth Digit | C++ Python | O(logn) | O(1) | Easy |||
413 | Arithmetic Slices | C++ Python | O(n) | O(1) | Medium |||
Sort
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
56| Merge Intervals| C++ Python | O(nlogn) | O(1) | Hard ||
57| Insert Interval| C++ Python | O(n) | O(1) | Hard ||
75| Sort Colors | C++ Python | O(n) | O(1) | Medium || Tri Partition
88| Merge Sorted Array| C++ Python | O(n) | O(1) | Easy ||
147| Insertion Sort List|C++ Python | O(n^2) | O(1) | Medium ||
148| Sort List | C++ Python | O(nlogn) | O(logn) | Medium ||
164| Maximum Gap | C++ Python| O(n) | O(n) | Hard || Tricky
179| Largest Number | C++ Python | O(nlogn) | O(1) | Medium ||
218| The Skyline Problem | C++ Python | O(nlogn) | O(n) | Hard || Sort, BST|
252| Meeting Rooms | C++ Python | O(nlogn) | O(n) | Easy |
Two Pointers
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
19| Remove Nth Node From End of List| C++ Python | O(n) | O(1) | Easy ||
86| Partition List| C++ Python | O(n) | O(1) | Medium ||
141| Linked List Cycle| C++ Python | O(n) | O(1) | Medium ||
142| Linked List Cycle II| C++ Python | O(n) | O(1) | Medium ||
143| Reorder List| C++ Python | O(n) | O(1) | Medium ||
167| Two Sum II - Input array is sorted | C++ Python | O(n) | O(1) | Medium | |
259 | 3Sum Smaller | C++ Python | O(n^2) | O(1) | Medium |
Recursion
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
95| Unique Binary Search Trees II | C++ Python | O(4^n / n^(3/2) | O(4^n / n^(3/2) | Medium ||
98| Validate Binary Search Tree|C++ Python| O(n) | O(1) | Medium ||
100| Same Tree |C+ Python | O(n) | O(h) | Easy ||
104| Maximum Depth of Binary Tree| C++ Python| O(n) | O(h) | Easy ||
105| Construct Binary Tree from Preorder and Inorder Traversal | C++ Python | O(n) | O(n) | Medium ||
106| Construct Binary Tree from Inorder and Postorder Traversal | C++ Python | O(n) | O(n) | Medium ||
108| Convert Sorted Array to Binary Search Tree | C++ Python | O(n) | O(logn) | Medium ||
109| Convert Sorted List to Binary Search Tree | C++ Python | O(n) | O(logn) | Medium ||
110| Balanced Binary Tree | Python | O(n)| O(h) | Easy ||
111| Minimum Depth of Binary Tree|Python| O(n) | O(h) | Easy ||
114| Flatten Binary Tree to Linked List|Python| O(n) | O(h) | Medium ||
116| Populating Next Right Pointers in Each Node|Python| O(n) | O(1) | Medium ||
124| Binary Tree Maximum Path Sum| Python | O(n)| O(h)| Hard ||
129| Sum Root to Leaf Numbers | Python | O(n) | O(h) | Medium ||
156| Binary Tree Upside Down | Python | O(n) | O(1) | Medium |
Binary Search
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
4| Median of Two Sorted Arrays | C++ Python | O(log(min(m, n))) | O(1) | Hard ||
33| Search in Rotated Sorted Array | C++ Python | O(logn) | O(1) | Hard ||
34| Search for a Range | C++ Python | O(logn) | O(1) | Medium ||
35| Search Insert Position | C++ Python | O(logn) | O(1) | Medium ||
69| Sqrt(x) | C++ Python | O(logn) | O(1) | Medium ||
74| Search a 2D Matrix | C++ Python | O(logm + logn) | O(1) | Medium ||
81| Search in Rotated Sorted Array II | C++ Python | O(logn) | O(1) | Medium ||
153| Find Minimum in Rotated Sorted Array | C++ Python | O(logn) | O(1) | Medium ||
154| Find Minimum in Rotated Sorted Array II | C++ Python | O(logn) ~ O(n) | O(1) | Hard ||
162| Find Peak Element | C++ Python | O(logn) | O(1) | Medium ||
222| Count Complete Tree Nodes | C++ Python | O((logn)^2) | O(1) | Medium ||
275| H-Index II | C++ Python | O(logn) | O(1) | Medium || Binary Search |
278| First Bad Version | C++ Python | O(logn) | O(1) | Easy | LintCode ||
300| Longest Increasing Subsequence | C++ Python | O(nlogn) | O(n) | Medium | CTCI, LintCode | Binary Search, DP|
302| Smallest Rectangle Enclosing Black Pixels| C++ Python | O(nlogn) | O(1) | Medium |
Binary Search Tree
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
220| Contains Duplicate III | C++ Python | O(nlogk) | O(k) | medium ||
230 | Kth Smallest Element in a BST | C++ Python | O(max(h, k)) | O(min(h, k)) | Medium ||
235 | Lowest Common Ancestor of a Binary Search Tree | C++ Python | O(h) | O(1) | Easy | EPI |
270| Closest Binary Search Tree Value| C++ Python | O(h) | O(1) | Easy |
Breadth-First Search
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
102| Binary Tree Level Order Traversal| C++ Python| O(n)| O(n)| Easy ||
107| Binary Tree Level Order Traversal II| Python | O(n)| O(n)| Easy ||
103| Binary Tree Zigzag Level Order Traversal| Python | O(n)| O(n)| Medium ||
117| Populating Next Right Pointers in Each Node II|Python| O(n) | O(1) | Hard ||
127| Word Ladder|Python | O(n * d) | O(d) | Medium ||
130| Surrounded Regions|C++ Python| O(m * n) | O(m + n) | Medium ||
133| Clone Graph| Python | O(n) | O(n) | Medium ||
207| Course Schedule| Python | O(|V| + |E|) | O(|E|) | Medium || Topological Sort |
210| Course Schedule II| Python | O(|V| + |E|) | O(|E|) | Medium || Topological Sort |
261| Graph Valid Tree| C++ Python | O(|V| + |E|) | O(|V| + |E|) | Medium |
Depth-First Search
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
112| Path Sum | Python | O(n) | O(h) | Easy ||
113| Path Sum II | Python | O(n) | O(h) | Medium ||
199| Binary Tree Right Side View | Python | O(n) | O(h) | Medium ||
200| Number of Islands | Python | O(m * n) | O(m * n)| Medium ||
236 | Lowest Common Ancestor of a Binary Tree | C++ Python | O(n) | O(h) | Medium | EPI |
247| Strobogrammatic Number II | C++ Python | O(n^2 * 5^(n/2)) | O(n) | Medium |
Backtracking
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
17| Letter Combinations of a Phone Number| Python | O(n * 4^n) | O(n) | Medium ||
22| Generate Parentheses| Python| O(4^n / n^(3/2)) | O(n) | Medium ||
37| Sudoku Solver | Python | O((9!)^9) | O(1) | Hard ||
39| Combination Sum| Python | O(k * n^k) | O(k) | Medium ||
40| Combination Sum II| Python| O(k * C(n, k))| O(k) | Medium ||
46| Permutations| Python | O(n * n!) | O(n) | Medium ||
47| Permutations II| Python | O(n * n!) | O(n) | Hard ||
51| N-Queens | Python | O(n!) | O(n) | Hard ||
52| N-Queens-II | Python | O(n!) | O(n) | Hard ||
77| Combinations | Python | O(n!) | O(n) | Medium ||
79| Word Search | Python | O(m * n * l) | O(l) | Medium ||
93| Restore IP Addresses | Python | O(1) | O(1) | Medium ||
78| Subsets | C++ Python | O(n * 2^n) | O(1) | Medium ||
90| Subsets II | C++ Python | O(n * 2^n) | O(1) | Medium ||
126| Word Ladder II |Python | O(n * d) | O(d) | Hard ||
131| Palindrome Partitioning | Python | O(n^2) ~ O(2^n) | O(n^2) | Medium ||
140| Word Break II | C++ Python | O(n * l^2 + n * r) | O(n^2) | Hard ||
212| Word Search II | C++ Python | O(m * n * l) | O(l) | Hard | LintCode | Trie, DFS
216| Combination Sum III| C++ Python | O(k * C(n, k)) | O(k) | Medium ||
254| Factor Combinations | C++ Python | O(nlogn) | O(logn) | Medium |
Dynamic Programming
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
10| Regular Expression Matching | Python | O(m * n) | O(n) | Hard ||
53| Maximum Subarray|Python| O(n) | O(1) | Medium ||
62| Unique Paths | Python| O(m * n) | O(m + n) | Medium ||
63| Unique Paths II | Python | O(m * n) | O(m + n) | Medium ||
64| Minimum Path Sum| Python| O(m * n) | O(m + n) | Medium ||
70| Climbing Stairs| Python | O(n) | O(1) | Easy ||
72| Edit Distance|Python| O(m * n) | O(m + n) | Hard ||
87| Scramble String | Python | O(n^4) | O(n^3) | Hard ||
91| Decode Ways | C++ Python| O(n) | O(1) | Medium ||
96| Unique Binary Search Trees | Python | O(n) | O(1) | Medium || Math
97| Interleaving String|Python| O(m * n) | O(m + n) | Hard ||
115| Distinct Subsequences|Python| O(n^2) | O(n) | Hard ||
120| Triangle | Python | O(m * n) | O(n) | Medium ||
123| Best Time to Buy and Sell Stock III | Python | O(n) | O(1) | Hard ||
132| Palindrome Partitioning II | Python | O(n^2) | O(n^2) | Hard ||
139| Word Break | C++ Python | O(n * l^2) | O(n) | Medium ||
152| Maximum Product Subarray|Python| O(n) | O(1) | Medium ||
174| Dungeon Game | Python| O(m * n) | O(m + n) | Hard ||
188| Best Time to Buy and Sell Stock IV| Python | O(k * n) | O(k) | Hard ||
198| House Robber| Python | O(n) | O(1) | Easy ||
213| House Robber II| C++ Python | O(n) | O(1) | Medium ||
221| Maximal Square| C++ Python | O(n^2) | O(n) | Medium | EPI |
256| Paint House | C++ Python | O(n)| O(1)| Medium |
Greedy
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| ----- 11| Container With Most Water| C++ Python | O(n) | O(1) | Medium || 42| Trapping Rain Water | C++ Python | O(n) | O(1) | Hard || Tricky 44| Wildcard Matching | Python | O(m + n) | O(1) | Hard || Tricky 45| Jump Game II | Python | O(n) | O(1) | Hard || 55| Jump Game | Python | O(n) | O(1) | Medium || 122| Best Time to Buy and Sell Stock II| Python | O(n) | O(1) | Medium || 134| Gas Station| Python | O(n) | O(1) | Medium || 135| Candy| C++ Python | O(n) | O(n) | Hard || 316| Remove Duplicate Letters | C++ Python | O(n)| O(k)| Medium || Ascending Stack | 321| Create Maximum Number| C++ Python | O(k * (m + n + k)) ~ O(k * (m + n + k^2))| O(m + n + k^2) | Hard | variant of Delete Digits | Greedy, DP 330| Patching Array | C++ Python | O(s + logn) | O(1) | Medium || 376| Wiggle Subsequence| C++ Python | O(n) | O(1) | Medium || 392| Is Subsequence| C++ Python | O(n) | O(1) | Medium || 397| Integer Replacement| C++ Python | O(n) | O(1) | Easy || Math 402 | Remove K Digits | C++ Python | O(n) | O(n) | Medium | LintCode |
Design
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| -----
284| Peeking Iterator| C++ Python | O(1) | O(1) | Medium ||
348| Design Tic-Tac-Toe | C++ Python | O(1)| O(n^2)| Medium |
SQL
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| ----- 175| Combine Two Tables | MySQL | O(m + n) | O(m + n) | Easy || 176| Second Highest Salary | MySQL | O(n) | O(1) | Easy || 177| Nth Highest Salary | MySQL | O(n^2) | O(n) | Medium || 178| Rank Scores | MySQL | O(n^2) | O(n) | Medium || 180| Consecutive Numbers | MySQL | O(n) | O(n) | Medium || 181| Employees Earning More Than Their Managers | MySQL | O(n^2) | O(1) | Easy || 182| Duplicate Emails | MySQL | O(n^2) | O(n) | Easy || 183| Customers Who Never Order | MySQL | O(n^2) | O(1) | Easy || 184| Department Highest Salary | MySQL | O(n^2) | O(n) | Medium || 185| Department Top Three Salaries | MySQL | O(n^2) | O(n) | Hard || 196| Delete Duplicate Emails | MySQL | O(n^2) | O(n) | Easy || 197| Rising Temperature | MySQL | O(n^2) | O(n) | Easy || 262| Trips and Users | MySQL | O((t * u) + tlogt) | O(t) | Hard ||
Shell Script
| Title | Solution | Time | Space | Difficulty | Tag | Note
-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------| ----- 192 | Word Frequency | Shell | O(n) | O(k) | Medium || 193 | Valid Phone Numbers | Shell | O(n) | O(1) | Easy || 194 | Transpose File | Shell | O(n^2) | O(n^2) | Medium || 195 | Tenth Line | Shell | O(n) | O(1) | Easy ||