13 |
Roman to integer |
String |
Solution |
Easy |
239 |
Sliding Window Maximum |
Queue |
Solution |
Hard |
387 |
First Unique Character in a String |
Hash |
Solution |
Easy |
2351 |
First Letter to Appear Twice |
Hash |
Solution |
Easy |
804 |
Unique Morse Code Words |
Hash |
Solution |
Easy |
1338 |
Reduce Array Size to The Half |
Heap |
Solution |
Medium |
876 |
Middle of the Linked List |
Linked List |
Solution |
Easy |
659 |
Split Array into Consecutive Subsequences |
Greedy |
Solution |
Medium |
342 |
Power of Four |
Math |
Solution |
Easy |
206 |
Reverse Linked List |
Linked List |
Solution |
Easy |
234 |
Palindrome Linked List |
Linked List |
Solution |
Easy |
383 |
Ransom Note |
Hash |
Solution |
Easy |
326 |
Power of Three |
Math |
Solution |
Easy |
412 |
Fizz Buzz |
String |
Solution |
Easy |
1337 |
The K Weakest Rows in a Matrix |
Heap |
Solution |
Easy |
1342 |
Number of Steps to Reduce a Number to Zero |
Bit manipulation |
Solution |
Easy |
1672 |
Richest Customer Wealth |
Array |
Solution |
Easy |
869 |
Reordered Power of 2 |
Math |
Solution |
Medium |
78 |
Subsets |
Tree |
Solution |
Medium |
1329 |
Sort the Matrix Diagonally |
Array |
Solution |
Medium |
48 |
Rotate Image |
Array |
Solution |
Medium |
1448 |
Count Good Nodes in Binary Tree |
Tree |
Solution |
Medium |
637 |
Average of Levels in Binary Tree |
Tree |
Solution |
Easy |
967 |
Numbers With Same Consecutive Differences |
Tree |
Solution |
Medium |
987 |
Vertical Order Traversal of a Binary Tree |
Tree |
Solution |
Hard |
429 |
N-ary Tree Level Order Traversal |
Tree |
Solution |
Medium |
814 |
Binary Tree Pruning |
Tree |
Solution |
Medium |
606 |
Construct String from Binary Tree |
Tree |
Solution |
Easy |
94 |
Binary Tree Inorder Traversal |
Tree |
Solution |
Easy |
1996 |
The Number of Weak Characters in the Game |
Stack |
Solution |
Medium |
188 |
Best Time to Buy and Sell Stock IV |
Dp |
Solution |
Hard |
1383 |
Maximum Performance of a Team |
Heap |
Solution |
Hard |
948 |
Bag of Tokens |
Two pointer |
Solution |
Medium |
393 |
UTF-8 Validation |
Bit manipulation |
Solution |
Medium |
1457 |
Pseudo-Palindromic Paths in a Binary Tree |
Tree, Bit manipulation |
Solution |
Medium |
2007 |
Find Original Array From Doubled Array |
Hash |
Solution |
Medium |
1770 |
Maximum Score from Performing Multiplication Operations |
Dp |
Solution |
Medium |
336 |
Palindrome Pairs |
String |
Solution |
Hard |
11 |
Container With Most Water |
Two pointer |
Solution |
Medium |
42 |
Trapping Rain Water |
Two pointer |
Solution |
Hard |
609 |
Find Duplicate File in System |
String |
Solution |
Medium |
718 |
Maximum Length of Repeated Subarray |
Dp |
Solution |
Medium |
985 |
Sum of Even Numbers After Queries |
Array |
Solution |
Medium |
557 |
Reverse Words in a String III |
String |
Solution |
Easy |
1680 |
Concatenation of Consecutive Binary Numbers |
Bit manipulation |
Solution |
Medium |
113 |
Path Sum II |
Tree |
Solution |
Medium |
622 |
Design Circular Queue |
Design, Queue |
Solution |
Medium |
990 |
Satisfiability of Equality Equations |
Union |
Solution |
Medium |
838 |
Push Dominoes |
String |
Solution |
Medium |
19 |
Remove Nth Node From End of List |
Linked List |
Solution |
Medium |
658 |
Find K Closest Elements |
Binary search |
Solution |
Medium |
218 |
The Skyline Problem |
Heap |
Solution |
Hard |
1 |
Two Sum |
Hash |
Solution |
Easy |
167 |
Two Sum II - Input Array Is Sorted |
Two pointer |
Solution |
Medium |
653 |
Two Sum IV - Input is a BST |
Tree |
Solution |
Easy |
1679 |
Max Number of K-Sum Pairs |
Hash |
Solution |
Medium |
15 |
3Sum |
Hash |
Solution |
Medium |
18 |
4Sum |
Hash |
Solution |
Medium |
1480 |
Running Sum of 1d Array |
Array |
Solution |
Easy |
724 |
Find Pivot Index |
Array |
Solution |
Easy |
205 |
Isomorphic Strings |
String, Hash |
Solution |
Easy |
392 |
Is Subsequence |
String, Two pointer |
Solution |
Easy |
21 |
Merge Two Sorted Lists |
Linked List |
Solution |
Easy |
142 |
Linked List Cycle II |
Linked List |
Solution |
Medium |
121 |
Best Time to Buy and Sell Stock |
Greedy |
Solution |
Easy |
409 |
Longest Palindrome |
Greedy |
Solution |
Easy |
589 |
N-ary Tree Preorder Traversal |
Tree |
Solution |
Easy |
102 |
Binary Tree Level Order Traversal |
Tree |
Solution |
Medium |
704 |
Binary Search |
Binary search |
Solution |
Easy |
278 |
First Bad Version |
Binary search |
Solution |
Easy |
98 |
Validate Binary Search Tree |
Tree |
Solution |
Medium |
235 |
Lowest Common Ancestor of a Binary Search Tree |
Tree |
Solution |
Medium |
733 |
Flood Fill |
Graph, DFS |
Solution |
Easy |
200 |
Number of Islands |
Graph, DFS |
Solution |
Medium |
509 |
Fibonacci Number |
Dp |
Solution |
Easy |
70 |
Climbing Stairs |
Dp |
Solution |
Easy |
746 |
Min Cost Climbing Stairs |
Dp |
Solution |
Easy |
62 |
Unique Paths |
Dp |
Solution |
Medium |
438 |
Find All Anagrams in a String |
Sliding Window |
Solution |
Medium |
424 |
Longest Repeating Character Replacement |
Sliding Window |
Solution |
Medium |
299 |
Bulls and Cows |
Hash |
Solution |
Medium |
844 |
Backspace String Compare |
Stack, Two pointer |
Solution |
Easy |
394 |
Decode String |
Stack |
Solution |
Medium |
1046 |
Last Stone Weight |
Heap |
Solution |
Easy |
692 |
Top K Frequent Words |
Heap |
Solution |
Medium |
217 |
Contains Duplicate |
Array |
Solution |
Easy |
238 |
Product of Array Except Self |
Array |
Solution |
Medium |
268 |
Missing Number |
Array, Math |
Solution |
Easy |
287 |
Find the Duplicate Number |
Two pointer |
Solution |
Medium |
448 |
Find All Numbers Disappeared in an Array |
Array |
Solution |
Easy |
9 |
Palindrome Number |
Math |
Solution |
Easy |
977 |
Squares of a Sorted Array |
Array |
Solution |
Easy |
169 |
Majority Element |
Array |
Solution |
Easy |
2022 |
Convert 1D Array Into 2D Array |
Array |
Solution |
Easy |
283 |
Move Zeroes |
Array |
Solution |
Easy |
88 |
Merge Sorted Array |
Array |
Solution |
Easy |
27 |
Remove Element |
Array |
Solution |
Easy |
26 |
Remove Duplicates from Sorted Array |
Array |
Solution |
Easy |
80 |
Remove Duplicates from Sorted Array II |
Array |
Solution |
Medium |
189 |
Rotate Array |
Array |
Solution |
Medium |
122 |
Best Time to Buy and Sell Stock II |
Array |
Solution |
Medium |
55 |
Jump Game |
Array |
Solution |
Medium |
45 |
Jump Game II |
Array |
Solution |
Medium |
274 |
H-Index |
Array |
Solution |
Medium |
134 |
Gas Station |
Array |
Solution |
Medium |
12 |
Integer to Roman |
String |
Solution |
Medium |
58 |
Length of Last Word |
String |
Solution |
Easy |
151 |
Reverse Words in a String |
String |
Solution |
Medium |
380 |
Insert Delete GetRandom O(1) |
Array |
Solution |
Medium |
14 |
Longest Common Prefix |
String |
Solution |
Easy |
28 |
Find the Index of the First Occurrence in a String |
String |
Solution |
Easy |
6 |
Zigzag Conversion |
String |
Solution |
Medium |
125 |
Valid Palindrome |
Two pointer |
Solution |
Easy |
1757 |
Recyclable and Low Fat Products |
Pandas |
Solution |
Easy |
209 |
Minimum Size Subarray Sum |
Sliding window |
Solution |
Medium |
290 |
Word Pattern |
Hash |
Solution |
Easy |
242 |
Valid Anagram |
Hash |
Solution |
Easy |
49 |
Group Anagrams |
Hash |
Solution |
Medium |
202 |
Happy Number |
Hash |
Solution |
Easy |
219 |
Contains Duplicate II |
Hash |
Solution |
Easy |
128 |
Longest Consecutive Sequence |
Hash |
Solution |
Medium |
228 |
Summary Ranges |
Intervals |
Solution |
Easy |
56 |
Merge Intervals |
Intervals |
Solution |
Medium |
57 |
Insert Interval |
Intervals |
Solution |
Medium |
452 |
Minimum Number of Arrows to Burst Balloons |
Intervals |
Solution |
Medium |
20 |
Valid Parentheses |
Stack |
Solution |
Easy |
71 |
Simplify Path |
Stack |
Solution |
Medium |