xuanjin001 / Leetcode

Leetcode Problem List

Leetcode Problem Sheet

Java (Round 1)

Total Count

	Easy	Medium	Hard	Unknown	Total
Round 1	18	26	0	1	45
Target	96	219	79		394
	24.4%	55.6%	20%
Round 2

Count	Leetcode #	Title	Difficulty	Date	Kind	Notes
1	283	Move Zeroes	Easy	3/28/2020	-	-
2	169	Majority Element	Easy	3/28/2020	-	-
3	448	Find All Numbers Disappeared in an Array	Easy	3/28/2020	-	Not understanding it
4	121	Best Time to Buy and Sell Stock	Easy	3/28/2020	-	-
5	53	Maximum Subarray	Easy	3/28/2020	-	Kadane's Algorithm
6	1	Two Sum	Easy	3/28/2020	Hashmap	-
7	581	Shortest Unsorted Continuous Subarray	Easy	3/28/2020	-	-
8	238	Product of Array Except Self	Medium	3/29/2020	-	-
9	78	Subsets	Medium	3/29/2020	Recursion	-
10	48	Rotate Image	Medium	3/29/2020	-	-
11	39	Combination Sum	Medium	3/29/2020	Recursion	-
12	287	Find the Duplicate Number	Medium	3/29/2020	-	-
13	75	Sort Colors	Medium	3/31/2020	Recursion	-
14	34	Find First and Last Position of Element in Sorted Array	Medium	3/31/2020	-	-
15	560	Subarray Sum Equals K	Medium	3/31/2020	Hashmap	-
16	739	Daily Temperatures	Medium	4/01/2020	-	-
17	136	Single Number	Easy	4/01/2020	Hash	-
18	347	Top K Frequent Elements	Medium	4/01/2020	Heap	-
19	3	Longest Substring Without Repeating Characters	Medium	4/01/2020	two pointers	-
20	141	Linked List Cycle	Easy	4/01/2020	-	-
21	142	Linked List Cycle II	Medium	4/01/2020	-	-
22	202	Happy Number	Easy	4/02/2020	-	Cannot really get my head around this one.
23	2	Add Two Numbers	Medium	4/02/2020	-	-
24	279	Perfect Squares	Medium	4/02/2020	-	-
25	21	Merge Two Sorted Lists	Easy	4/02/2020	-	-
*	review	stop	here	:---:	:---:	*
*	review	below	items	:---:	:---:	*
26	148	Sort List	Medium	4/05/2020	-	-
27	206	Reverse Linked List	Easy	4/05/2020	-	-
28	19	Remove Nth Node From End of List	Medium	4/05/2020	-	-
29	122	Best Time to Buy and Sell Stock II	Easy	4/05/2020	-	-
30	15	3Sum	Medium	4/06/2020	-	-
31	160	Construct Binary Tree from Inorder and Postorder Traversal	Easy	4/06/2020	-	-
32	49	Group Anagrams	Medium	4/06/2020	-	-
33	56	Merge Intervals	Medium	4/06/2020	-	-
34	79	Word Search	Medium	4/06/2020	-	-
35	20	Validate Parentheses	Easy	4/06/2020	-	-
*	review	above	items	:---:	:---:	*
36	#	Counting Elements	*	4/07/2020	HashSet	This one is not part of the listed LeetCode problem
37	155	Min Stack	Easy	4/07/2020	-	-
38	876	Middle of the Linked List	Easy	4/08/2020	-	-
39	438	Find All Anagrams in a String	Medium	4/08/2020	Sliding Window	Close to #76
40	5	Longest Palindromic Substring	Medium	4/08/2020	Sliding Window	-
41	217	Contains Duplicate	Easy	4/08/2020	HashSet	-
42	152	Maximum Product Subarray	Medium	4/08/2020	-	-
43	33	Search in Rotated Sorted Array	Medium	4/08/2020	Binary Search	-
44	153	Find Minimum in Rotated Sorted Array	Medium	4/08/2020	Binary Search	-
45	424	Longest Repeating Character Replacement	Medium	4/08/2020	Sliding Window	-
	Count	Stopped	Here	:---:	:---:	*
46	844	Backspace String Compare	Easy	4/09/2020	-	-
47	22	Generate Parentheses	Medium	4/09/2020	Backtracking	This is the first backtracking problem, contains notes on what's backtracking and how to set up the problems
48	784	Letter Case Permutation	Easy	4/09/2020	Backtracking	-
49	17	Letter Combinations of a Phone Number	Medium	4/09/2020	Backtracking: faster; Queue, permutation method: slow	-
50	394	Decode String	Medium	4/09/2020	String	-
	:--:	:---:	:---:	:---:	:---:	*
51	698	Partition to K Equal Sum Subsets	Medium	4/10/2020	Recursion, Backtracking	-
52	543	Diameter of Binary Tree	Easy	4/11/2020	-	-
53	1046	Last Stone Weight	Easy	4/12/2020	-	-

I started to prepare for another form of interview, so kinda slacked off on this, the following problem will need a redo...

Count	Leetcode #	Title	Difficulty	Date	Kind	Notes
54	#	Perform String Shifts	*	-	-	-
55	678		*	-	-	-
56	525	Contiguous Array	*	-	-	-
57	200	Number of Island	*	-	-	-
58	64	Minimum Path Sum	Medium	-	-	-
59			LeftmostColumnwithatLeastAOne.md	-	-	-
60	146	LRU Cache	*	-	-	-
61	#	Binary Tree Maximum Path Sum	*	-	-	-
62		First Bad Version	*	-	-	-
63	771	Jewels And Stones	*	-	-	-
64	383	Ransom Note	*	-	-	-
*			*	-	-	-
*			*	-	-	-
*			*	-	-	-
*	40	Combination Sum II	Medium	-
*	494	Target Sum	Medium	4/08/2020	DP	Not understanding this at all
*	680		Easy	-	-	-
	:--:	:---:	:---:	:---:	:---:	*
*	46		Medium	-	-	-
*	101		Easy	-	-	-
*	98	Validate Binary Search Tree	Medium	-	-	-
	:--:	:---:	:---:	:---:	:---:	*
*	300	Longest Increasing Subsequence	Medium	-	-	-
*	200		Medium	-	-	-
*	11	Container With Most Water	Medium	-	-	-
*	7	Reverse Integer	Easy	-	-	-
*	76		Hard	-	-	-
	:--:	:---:	:---:	:---:	:---:	*
#	204	Count Primes	Easy	-	-	-
*	:--:	:---:	:---:	:---:	:---:	*
#	88	Merge Sorted Array	Easy	-	-	-
*	647		Medium	-	String, DP	-
*	417		Medium	-	BFS, DFS	-
#	62		Medium	-	-	-
#	621		Medium	-	-	-
#	105		Medium	-	-	-
#	55		Medium	-	-	-
	:---:	:---:	:---:	:---:	:---:
*			*	-	-	-

Java (Round 2)

Count	Leetcode #	Title	Difficulty	Date	Kind	Notes
1	283	Move Zeroes	Easy	3/28/2020	-	-
2	169	Majority Element	Easy	3/28/2020	-	-
3	448	Find All Numbers Disappeared in an Array	Easy	3/28/2020	-	Not understanding it
4	121	Best Time to Buy and Sell Stock	Easy	3/28/2020	-	-
5	53	Maximum Subarray	Easy	3/28/2020	-	Kadane's Algorithm

Area for improvement

• Need more work on Stack (4/09/2020)
• Did couple backtracking problems, need more practice (4/09/2020)
• Need to go over heap sort (4/09/2020)
• Need #39, #40 for recursion (4/09/2020)
• Review on merge sort (4/09/2020)

Sit aside contents:

https://www.youtube.com/watch?v=7fujbpJ0LB4

Hard Array

#	Title	Difficulty	Date	Kind	Notes
42		Hard	-	-	-
128		Hard	-	-	-
85		Hard	-	-	-
84		Hard	-	-	-
41		Hard	-	-	-
45		Hard	-	-	-
4		Hard	-	-	-

Maybe Pile

(Those problems I should practice when I have time)

#	Title	Difficulty	Date	Kind	Notes
167	Two Sum II - Input array is sorted	Medium	-	-	-
90	-	Medium	-	-	-
18	4Sum	Medium	-	-	-
35	Search Insert Position	Easy	-	-	-

Python

Python will be on pause, I found that Python is easy to do problem and so

But I need to search for some python functions while I am doing the problem

#	Title	Difficulty	Date	Kind	Notes
283	Move Zeroes	Easy	3/28/2020	-	-
169	Majority Element	Easy	3/28/2020	-	-
448	Find All Numbers Disappeared in an Array	Easy	3/28/2020	-	-
121	Best Time to Buy and Sell Stock	Easy	3/28/2020	-	-
53	Maximum Subarray	Easy	3/28/2020	-	-
1	Two Sum	Easy	3/28/2020	-	-
581	Shortest Unsorted Continuous Subarray	Easy	3/28/2020	-	-

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