| 1 |
Two-Sum |
Array |
Easy |
Solution |
| 561 |
Array Partition |
Array |
Easy |
Solution |
| 1295 |
Find Numbers with Even Number of Digits |
Array |
Easy |
Solution |
| 1672 |
Richest Customer Wealth |
Array |
Easy |
Solution |
| 1920 |
Build Array from Permutation |
Array |
Easy |
Solution |
| 1929 |
Concatenation of Array |
Array |
Easy |
Solution |
| 1480 |
Running Sum of 1d Array |
Array |
Easy |
Solution |
| 1470 |
Shuffle the Array |
Array |
Easy |
Solution |
| 804* |
Unique Morse Code Words |
Array,Hash Table |
Easy |
Solution |
| 1512 |
Number of Good Pairs |
Array |
Easy |
Solution |
| 485 |
Max Consecutive Ones |
Array |
Easy |
Solution |
| 1365 |
How Many Numbers Are Smaller Than the Current Number |
Array, Sorting, Hash Table |
Easy |
Solution |
| 1389 |
Create Target Array in the Given Order |
Array, ArrayList |
Easy |
Solution |
| 1773 |
Count Items Matching a Rule |
Array, String |
Easy |
Solution |
| 1732 |
Find the Highest Altitude |
Array, Prfix Sum |
Easy |
Solution |
| 832 |
Flipping an Image |
Array, Matrix, Two pointers |
Easy |
Solution |
| 234 |
Palindrome Linked List |
LinkedList, Two Pointer, Recursion, Stack |
Easy |
Solution |
| 342 |
Power of Four |
Math, Bit Manipulation, Recursion |
Easy |
Solution |
| 383 |
Ransom Note |
Hash Table, Counting, String |
Easy |
Solution |
| 326 |
Power of Three |
Math, Recursion |
Easy |
Solution |
| 1252 |
Cells with Odd Values in a Matrix |
Array, Math |
Easy |
Solution |
| 1572 |
Matrix Diagonal Sum |
Array, Matrix |
Easy |
Solution |
| 867 |
Transpose Matrix |
Array, Matrix, Simulation |
Easy |
Solution |
| 989 |
Add to Array-Form of Integer |
Array, Math |
Easy |
Solution |
| 1854 |
Maximum Population Year |
Array, Counting |
Easy |
Solution |
| 1886 |
Determine Whether Matrix Can Be Obtained By Rotation |
Array, Matrix |
Easy |
Solution |
| 26 |
Remove Duplicate from Sorted Array |
Array, Two Pointers |
Easy |
Solution |
| 66 |
Plus One |
Math, Array |
Easy |
Solution |
| 724 |
Find Pivot Index |
Array, Prefix Sum |
Easy |
Solution |
| 463 |
Island Perimeter |
Array, Matrix |
Easy |
Solution |
| 136 |
Single Number |
Array, Bit Manipulation |
Easy |
Solution |
| 27 |
Remove Element |
Array, Two Pointers |
Easy |
Solution |
| 217 |
Contains Duplicate |
Array, Hash Table, Sorting |
Easy |
Solution |
| 219 |
Contains Duplicate II |
Array, Hash Table, Sliding Window |
Easy |
Solution |
| 977 |
Squares of a Sorted Array |
Array, Two Pointers, Sorting |
Easy |
Solution |
| 121 |
Best Time to Buy and Sell Stock |
Array (Without DP) |
Easy |
Solution |
| 448 |
Find All Numbers Disappeared in an Array |
Array, Hash Table |
Easy |
Solution |
| 645 |
Set Mismatch |
Array, Hash Table, Bit Manipulation, Sorting |
Easy |
Solution |
| 704 |
Binary Search |
Array, Binary Search |
Easy |
Solution |
| 69 |
Sqrt(x) |
Math, Binary Search |
Easy |
Solution |
| 374 |
Guess Number Higher or Lower |
Binary Search |
Easy |
Solution |
| 278 |
First Bad Version |
Binary Search |
Easy |
Solution |
| 744 |
Find Smallest Letter Greater Than Target |
Array, Binary Search |
Easy |
Solution |
| 1351 |
Count Negative Numbers in a Sorted Matrix |
Array, Binary Search, Matrix |
Easy |
Solution |
| 349 |
Intersection of Two Array |
Array, Binary Search,Two Pointers, Hash Table, Sorting |
Easy |
Solution |
| 350 |
Intersection of Two Arrays II |
Array, Hash Table, Two Pointers, Binary Search, Sorting |
Easy |
Solution |
| 268 |
Missing Number |
Array, Binary Search, Math, Hash Table, Sorting, Bit Manipulation |
Easy |
Solution |
| 441 |
Arranging Coins |
Array, Binary Search |
Easy |
Solution |
| 35 |
Search Insert Position |
Array, Binary Search |
Easy |
Solution |
| 169 |
Majority Element |
Array, Moore Voting Algorithm |
Easy |
Solution |
| 1108 |
Defanging an IP Address |
String |
Easy |
Solution |
| 520 |
Detect Capital |
Strings |
Easy |
Solution |
| 344 |
Reverse String |
Two Pointers, String |
Easy |
Solution |
| 412 |
Fizz Buzz |
String, Math, Simulation |
Easy |
Solution |
| 859 |
Buddy Strings |
Strings, Hash Table |
Easy |
Solution |
| 13 |
Roman to Integer |
String, Hash Table, Math |
Easy |
Solution |
| 1768 |
Merge Strings Alternately |
String, Two Pointers |
Easy |
Solution |
| 1528 |
Shuffle String |
Array, String |
Easy |
Solution |
| 7 |
Reverse Integer |
Math, Loops |
Medium |
Solution |
| 172 |
Factorial Trailing Zeroes |
Math, Loops |
Medium |
Solution |
| 50 |
Pow(x,n) |
Math, Loops (Without Recursion) |
Medium |
Solution |
| 869 |
Reordered Power of 2 |
Math, Sorting |
Medium |
Solution |
| 1338 |
Reduce Array Size to The Half |
Array |
Medium |
Solution |
| 659 |
Split Array into Consecutive Subsequences |
Array |
Medium |
Solution |
| 1329 |
Sort the Matrix Diagonally |
Array, Sorting, Matrix |
Medium |
Solution |
| 48 |
Rotate Image |
Array, Math, Matrix |
Medium |
Solution |
| 55 |
Jump Game |
Array, DP, Greedy |
Medium |
Solution |
| 75 |
Sort Colors |
Array, Two Pointers, Sorting |
Medium |
Solution |
| 137 |
Single Number II |
Array, Bit Manipulation |
Medium |
Solution |
| 1493 |
Longest Subarray of 1's After Deleting One Element |
Array (Without DP) |
Medium |
Solution |
| 442 |
Find All Duplicate in an Array |
Array, Hash Table |
Medium |
Solution |
| 189 |
Rotate Array |
Array, Math, Two Pointers |
Medium |
Solution |
| 34 |
Find First and Last Position of Element in Sorted Array |
Array, Binary Search |
Medium |
Solution |
| 852 |
Peak Index in a Mountain Array |
Array, Binary Search |
Medium |
Solution |
| 162 |
Find Peak Element |
Array, Binary Search |
Medium |
Solution |
| 33 |
Search in Rotated Sorted Array |
Array, Binary Search |
Medium |
Solution |
| 81 |
Search in Rotated Sorted Array II |
Array, Binary Search |
Medium |
Solution |
| 153 |
Find Minimum in Rotated Sorted Array |
Array, Binary Search |
Medium |
Solution |
| 754 |
Reach a Number |
Math, Binary Search |
Medium |
Solution |
| 74 |
Search a 2D Matrix |
Array, Binary Search, Matrix |
Medium |
Solution |
| 436 |
Find Right Interval |
Array, Binary Search, Sorting |
Medium |
Solution |
| 209 |
Minimum Size Subarray Sum |
Array, Binary Search, Prefix Sum, SW |
Medium |
Solution |
| 2300 |
Successful Pairs of Spells and Potions |
Array, Binary Search, Sorting, Two Pointers |
Medium |
Solution |
| 287 |
Find the Duplicate Number |
Array, Binary Search, Two Pointers, Bit Manipulation |
Medium |
Solution |
| 707 |
Design Linked List |
Linked List, Design |
Medium |
Solution |
| 363 |
Max Sum of Rectangle No Larger Than K |
Array, Binary Search, Matrix, Prefix Sum, Ordered Set |
Hard |
Solution |
| 871 |
Minimum Number of Refueling Stops |
Array, DP |
Hard |
Solution |
| 41 |
First Missing Number |
Array, Hash Table |
Hard |
Solution |
| 1095 |
Find in Mountain Array |
Array, Binary Search |
Hard |
Solution |
| 410 |
Split Array Largest Sum |
Array, Binary Search, Prefix Sum |
Hard |
Solution |
| 4 |
Median of Two Sorted Arrays |
Array, Binary Search |
Hard |
Solution |