As the saying goes: “Practice makes you better"

Below record my solution and all my problem-sovling ideas, hope you have a good time.

No	Title	Solution	Difficulty	Runtime	Memory	Memo
1	Two Sum	Go, Java	Easy	99.91%	5.65%
2	Add Two Numbers	Java	Medium
3	Longest Substring Without Repeating Characters	Java	Medium
4	Median of Two Sorted Arrays	Java	Hard
5	Longest Palindromic Substring	Java	Medium
7	Reverse Integer	Go, Java	Easy	100%	5.55%
8	String To Integer(atoi)	Java	Medium
9	Palindrome Number	Go, Java	Easy
10	Regular Expression Matching	Java	Hard
11	Container With Most Water	Java	Medium
12	Integer To Roman	Java	Medium
13	Roman To Integer	Java	Easy
14	Longest Common Prefix	Java	Easy	100%	5.48%
17	Letter Combinations of a Phone Number	Go	Medium	100%	78.41%
19	Remove Nth Node From End of List	Go	Medium	100%	78.41%
20	Valid Parentheses	Go	Easy	100%	99.53%
21	Merge Two Sorted Lists	Go	Easy
26	Remove Duplicates from Sorted Array	Go	Easy	92.44%	82.73%
36	Valid Sudoku	Go	Medium	100%	92.59%
53	Maximum Subarray	Go	Medium	64.52%	58.13%	F/U[x]
62	Unique Paths	Go	Medium	100.00%	75.66%
66	Plus One	Go	Easy	100.00%	64.91%
69	Sqrt(x)	Go	Easy	100%	82.21%
70	Climbing Stairs	Go	Easy	100%	91.21%
74	Search a 2D Matrix	Go	Medium	%	%
83	Remove Duplicates from Sorted List	Go	Easy	89.65%	85.61%
88	Merge Sorted Array	Go	Easy	100%	85.10%	F/U[v]
94	Binary Tree Inorder Traversal	Go	Easy	100%	27.93%
98	Validate Binary Search Tree	Go	Medium	100%	85.09%
101	Symmetric Tree	Go	Easy	100%	100%	F/U[x]
102	Binary Tree Level Order Traversal	Go	Medium	67.53%	89.92%
104	Maximum Depth of Binary Tree	Go	Easy	82.43%	62.31%
108	Convert Sorted Array to Binary Search Tree	Go	Easy	100%	100%
112	Path Sum	Go	Easy	92.41%	78.45%
118	Pascal's Triangle	Go	Easy	100%	86.92%
121	Best Time to Buy And Sell Stock	Go	Easy
136	Single Number	Go	Easy
141	Linked List Cycle	Go	Easy	100%	100%	F/U[v]
142	Linked List Cycle II	Go	Easy	28.12%	12.07%
144	Binary Tree Preorder Traversal	Go	Easy	12.62%	40.97%
145	Binary Tree Postorder Traversal	Go	Easy	100%	90.24%
160	Intersection of Two Linked Lists	Go	Easy	34.35%	44.19%	F/U[x]
169	Majority Element	Go	Easy	75.69%	99.31%	F/U[x]
171	Excel Sheet Column Number	Go	Easy	%	%
190	Reverse Bits	Go	Easy	100%	69.90%
191	Number of 1 Bits	Go	Easy	100%	92.10%
200	Numbers of Islands	Go	Medium	90.84%	46.68%
202	Happy Number	Go	Easy	%	%
203	Remove Linked List Elements	Go	Easy	90.19%	5.19%
205	Isomorphic Strings	Go	Easy
206	Reverse Linked List	Go	Easy
217	Contains Duplicate	Go	Easy
226	Invert Binary Tree	Go	Easy	100%	70.21%
232	Implement Queue using Stacks	Go	Easy	100%	85.17%	F/U[v]
235	Lowest Common Ancestor of a Binary Search Tree	Go	Medium
238	Product of Array Except Self	Go	Medium
242	Valid Anagram	Go	Easy	100%	100%
268	Missing Number	Go	Easy
278	First Bad Version	Go	Easy	100.00%	87.98%	⭐️
299	Bulls and Cows	Go	Medium	100.00%	100.00%	⭐️
350	Intersection of Two Arrays II	Go	Easy	29.62%	11.85%
383	Ransom Note	Go	Easy
387	First Unique Character in a String	Go	Easy	94.03%	94.36%
392	Is Subsequence	Go	Easy
394	Decode String	Go	Medium	100%	93.38%
409	Longest Palindrome	Go	Easy
424	Longest Repeating Character Replacement	Go	Medium	100%	79.23%
438	Find All Anagrams in a String	Go	Medium	84.02%	56.20%
448	Find All Numbers Disappeared in an Array	Go	Easy
509	Finonacci Number	Go	Easy	21.35%	34.38%
566	Reshape the Matrix	Go	Easy	53.81%	72.03%	O/P[x]
589	N-ary Tree Preorder Traversal	Go	Easy	100%	79.22%
653	Two Sum IV - Input is a BST	Go	Easy	84.35%	87.15%
692	Top K Frequent Words	Go	Medium			F/U[x]
700	Search in a Binary Search Tree	Go	Easy	92.16%	90.46%
701	Insert Into a Binary Search Tree	Go	Medium	95.85%	80.83%
704	Binary Search	Go	Easy	91.93%	94.44%
724	Find Pivot Index	Go	Easy
733	Flood Fill	Go	Easy	33.70%	18.72%
746	Min Cost Climbing Stairs	Go	Easy	100%	43.33%
844	Backspace String Compare	Go	Easy	100%	100%
876	Middle of the Linked List	Go	Easy
1046	Last Stone Weight	Go	Easy	100%	82.70%
1143	Longest Common Subsequence	Java	Medium	45.08%	100%
1480	Running Sum of 1d Array	Go	Easy	73.56%	45.55%