| # | Problem | Category | Difficulty | Solution |
|---|---|---|---|---|
| 2235 | Add Two Integers | Math | Easy | Solution |
| 1281 | Subtract the Product and Sum of Digits of an Integer | Loops, Math | Easy | Solution |
| 338 | Counting Bits | Bit Manipulation | Easy | Solution |
| 9 | Palindrome Number | Math, Loops | Easy | Solution |
| # | Problem | Category | Difficulty | Solution |
|---|---|---|---|---|
| 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 |
| # | Problem | Category | Difficulty | Solution |
|---|---|---|---|---|
| 387 | First Unique Character in a String | Strings, Hash Table | Easy | Solution |
| 1832 | Check if the Sentence Is Pangram | Strings, Hash Table | Easy | Solution |
| 1773 | Count Items Matching a Rule | Array, String | Easy | Solution |