1 |
Two Sum |
Easy |
Array
|
Hash Table
|
4 |
Median of Two Sorted Arrays |
Hard |
Array
|
Binary Search
|
Divide and Conquer
|
15 |
3Sum |
Medium |
Array
|
Two Pointers
|
16 |
3Sum Closest |
Medium |
Array
|
Two Pointers
|
18 |
4Sum |
Medium |
Array
|
Hash Table |
Two Pointers
|
26 |
Remove Duplicates from Sorted Array |
Easy |
Array
|
Two Pointers
|
27 |
Remove Element |
Easy |
Array
|
Two Pointers
|
31 |
Next Permutation |
Medium |
Array
|
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
|
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
|
45 |
Jump Game II |
Hard |
Array
|
Greedy
|
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
|
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
|
105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Medium |
Array
|
Tree
|
Depth-first Search
|
106 |
Construct Binary Tree from Inorder and Postorder Traversal |
Medium |
Array
|
Tree
|
Depth-first Search
|
118 |
Pascal's Triangle |
Easy |
Array
|
119 |
Pascal's Triangle II |
Easy |
Array
|
120 |
Triangle |
Medium |
Array
|
Dynamic Programming
|
121 |
Best Time to Buy and Sell Stock |
Easy |
Array
|
Dynamic Programming
|
122 |
Best Time to Buy and Sell Stock II |
Easy |
Array
|
Greedy
|
123 |
Best Time to Buy and Sell Stock III |
Hard |
Array
|
Dynamic Programming
|
126 |
Word Ladder II |
Hard |
Array
|
String
|
Backtracking |
Breadth-first Search
|
152 |
Maximum Product Subarray |
Medium |
Array
|
Dynamic Programming
|
1208 |
Get Equal Substrings Within Budget |
Medium |
Array
|
Sliding Window
|
1266 |
Minimum Time Visiting All Points |
Easy |
Array
|
Geometry
|
1267 |
Count Servers that Communicate |
Medium |
Array
|
Graph
|
1275 |
Find Winner on a Tic Tac Toe Game |
Easy |
Array
|
1277 |
Count Square Submatrices with All Ones |
Medium |
Array
|
Dynamic Programming
|
1295 |
Find Numbers with Even Number of Digits |
Easy |
Array
|
1296 |
Divide Array in Sets of K Consecutive Numbers |
Medium |
Array
|
Greedy
|
1346 |
Check If N and Its Double Exist |
Easy |
Array
|
1351 |
Count Negative Numbers in a Sorted Matrix |
Easy |
Array
|
Binary Search
|
1352 |
Product of the Last K Numbers |
Medium |
Array
|
Design
|
1365 |
How Many Numbers Are Smaller Than the Current Number |
Easy |
Array
|
Hash Table
|
1366 |
Rank Teams by Votes |
Medium |
Array
|
Sort
|
1375 |
Bulb Switcher III |
Medium |
Array
|
1380 |
Lucky Numbers in a Matrix |
Easy |
Array
|
1389 |
Create Target Array in the Given Order |
Easy |
Array
|
1748 |
Sum of Unique Elements |
Easy |
Array
|
Hash Table
|
1758 |
Minimum Changes To Make Alternating Binary String |
Easy |
Array
|
Greedy
|
1764 |
Form Array by Concatenating Subarrays of Another Array |
Medium |
Array
|
Greedy
|
1769 |
Minimum Number of Operations to Move All Balls to Each Box |
Medium |
Array
|
Greedy
|