Solution for 1-100


77/100

16
47
14
# Name Difficulty Tags
1 Two Sum Easy Array | Hash Table
2 Add Two Numbers Medium Linked List | Math
3 Longest Substring Without Repeating Characters Medium Hash Table | Two Pointers | String | Sliding Window
4 Median of Two Sorted Arrays Hard Array | Binary Search | Divide and Conquer
5 Longest Palindromic Substring Medium Dynamic Programming | String
6 ZigZag Conversion Medium String
7 Reverse Integer Easy Math
8 String to Integer (atoi) Medium Math | String
9 Palindrome Number Easy Math
10 Regular Expression Matching Hard String | Dynamic Programming | Backtracking
11 Container With Most Water Medium TBD
12 Integer to Roman Medium Math | String
13 Roman to Integer Easy Math | String
14 Longest Common Prefix Easy String
15 3Sum Medium Array | Two Pointers
16 3Sum Closest Medium Array | Two Pointers
17 Letter Combinations of a Phone Number Medium String | Backtracking | Depth-first search | Recursion
18 4Sum Medium Array | Hash Table | Two Pointers
19 Remove Nth Node From End of List Medium Linked List | Two Pointers
20 Valid Parentheses Easy String | Stack
21 Merge Two Sorted Lists Easy Linked List | Recursion
22 Generate Parentheses Medium String | Backtracking
23 Merge k Sorted Lists Hard Linked List | Divide and Conquer | Heap
24 Swap Nodes in Pairs Medium Linked List | Recursion
25 Reverse Nodes in k-Group Hard Linked List
26 Remove Duplicates from Sorted Array Easy Array | Two Pointers
27 Remove Element Easy Array | Two Pointers
28 Implement strStr() Easy Two Pointers | String
29 Divide Two Integers Medium Math | Binary Search
30 Substring with Concatenation of All Words Hard Hash Table | Two Pointers | String
31 Next Permutation Medium Array
32 Longest Valid Parentheses Hard String | Dynamic Programming
33 Search in Rotated Sorted Array Medium Array | Binary Search
34 Find First and Last Position of Element in Sorted Array Medium Array | Binary Search
35 Search Insert Position Easy Array | Binary Search
36 Valid Sudoku Medium Hash Table
37 Sudoku Solver Hard Hash Table | Backtracking
38 Count and Say Medium String
39 Combination Sum Medium Array | Backtracking
40 Combination Sum II Medium Array | Backtracking
41 First Missing Positive Hard Array
42 Trapping Rain Water Hard Array | Two Pointers | Stack
43 Multiply Strings Medium Math | String
44 Wildcard Matching Hard String | Dynamic Programming | Backtracking | Greedy
45 Jump Game II Hard Array | Greedy
46 Permutations Medium Backtracking
47 Permutations II Medium Backtracking
48 Rotate Image Medium Array
53 Maximum Subarray Easy Array | Divide and Conquer | Dynamic Programming
54 Spiral Matrix Medium Array
55 Jump Game Medium Array | Greedy
56 Merge Intervals Medium Array | Sort
57 Insert Interval Medium Array | Sort
58 Length of Last Word Easy String
59 Spiral Matrix II Medium Array
62 Unique Paths Medium Array | Dynamic Programming
63 Unique Paths II Medium Array | Dynamic Programming
64 Minimum Path Sum Medium Array | Dynamic Programming
66 Plus One Easy Array
73 Set Matrix Zeroes Medium Array
74 Search a 2D Matrix Medium Array | Binary Search
75 Sort Colors Medium Array | Two Pointers | Sort
78 Subsets Medium Array | Backtracking | Bit Manipulation
79 Word Search Medium Array | Backtracking
80 Remove Duplicates from Sorted Array II Medium Array | Two Pointers
81 Search in Rotated Sorted Array II Medium Array | Binary Search
84 Largest Rectangle in Histogram Hard Array | Stack
85 Maximal Rectangle Hard Array | Hash Table | Dynamic Programming | Stack
88 Merge Sorted Array Easy Array | Two Pointers
90 Subsets II Medium Array | Backtracking
92 Reverse Linked List II Medium Linked List
94 Binary Tree Inorder Traversal Medium Tree | Hash Table | Stack
95 Unique Binary Search Trees II Medium Dynamic Programming | Tree
96 Unique Binary Search Trees Medium Dynamic Programming | Tree
98 Validate Binary Search Tree Medium Tree | Depth-first Search
99 Recover Binary Search Tree Hard Tree | Depth-first Search
100 Same Tree Easy Tree | Depth-first Search