All 173 problems solved in Java — auto-updated on every push. Last updated: 24 Jul 2026, 05:30 UTC
| 🟢 Easy | 🟡 Medium | 🔴 Hard | Total |
|---|---|---|---|
| 102 | 54 | 17 | 173 |
| # | Problem | Difficulty | Topic | Date Solved |
|---|---|---|---|---|
| 1 | Two Sum | 🟢 Easy | Arrays |
2026-04-10 |
| 2 | Add Two Numbers | 🟡 Medium | LinkedList |
2026-07-18 |
| 3 | Longest Substring Without Repeating Characters | 🟡 Medium | SlidingWindow |
2026-05-01 |
| 5 | Longest Palindromic Substring | 🟡 Medium | Strings |
2026-05-08 |
| 9 | Palindrome Number | 🟢 Easy | Strings |
2026-04-12 |
| 13 | Roman to Integer | 🟢 Easy | Strings |
2026-05-01 |
| 14 | Longest Common Prefix | 🟢 Easy | Arrays |
2026-04-29 |
| 17 | Letter Combinations of a Phone Number | 🟡 Medium | Strings |
2026-07-04 |
| 20 | Valid Parentheses | 🟢 Easy | Strings |
2026-05-03 |
| 22 | Generate Parentheses | 🟡 Medium | Strings |
2026-07-04 |
| 26 | Remove Duplicates from Sorted Array | 🟢 Easy | Arrays |
2026-04-17 |
| 27 | Remove Element | 🟢 Easy | Arrays |
2026-05-28 |
| 28 | Find the Index of the First Occurrence in a String | 🟢 Easy | Strings |
2026-04-12 |
| 33 | Search in Rotated Sorted Array | 🟡 Medium | BinarySearch |
2026-04-05 |
| 34 | Find First and Last Position of Element in Sorted Array | 🟡 Medium | BinarySearch |
2026-04-03 |
| 35 | Search Insert Position | 🟢 Easy | BinarySearch |
2026-04-08 |
| 41 | First Missing Positive | 🔴 Hard | Arrays |
2026-04-16 |
| 58 | Length of Last Word | 🟢 Easy | Strings |
2026-04-17 |
| 66 | Plus One | 🟢 Easy | Numbers |
2026-04-12 |
| 67 | Add Binary | 🟢 Easy | TwoPointers |
2026-05-05 |
| 69 | Sqrt(x) | 🟢 Easy | BinarySearch |
2026-05-20 |
| 70 | Climbing Stairs | 🟢 Easy | DynamicProgramming |
2026-06-10 |
| 74 | Search a 2D Matrix | 🟡 Medium | Arrays |
2026-04-24 |
| 75 | Sort Colors | 🟡 Medium | Arrays |
2026-04-27 |
| 81 | Search in Rotated Sorted Array II | 🟡 Medium | BinarySearch |
2026-04-06 |
| 88 | Merge Sorted Array | 🟢 Easy | Arrays |
2026-05-07 |
| 118 | Pascal's Triangle | 🟢 Easy | Arrays |
2026-05-15 |
| 119 | Pascal's Triangle II | 🟢 Easy | DynamicProgramming |
2026-06-10 |
| 121 | Best Time to Buy and Sell Stock | 🟢 Easy | Arrays |
2026-06-04 |
| 122 | Best Time to Buy and Sell Stock II | 🟡 Medium | Arrays |
2026-06-05 |
| 125 | Valid Palindrome | 🟢 Easy | TwoPointers |
2026-04-28 |
| 136 | Single Number | 🟢 Easy | Arrays |
2026-04-25 |
| 151 | Reverse Words in a String | 🟡 Medium | Strings |
2026-04-25 |
| 153 | Find Minimum in Rotated Sorted Array | 🟡 Medium | BinarySearch |
2026-04-08 |
| 154 | Find Minimum in Rotated Sorted Array II | 🔴 Hard | BinarySearch |
2026-04-08 |
| 162 | Find Peak Element | 🟡 Medium | BinarySearch |
2026-04-04 |
| 169 | Majority Element | 🟢 Easy | Arrays |
2026-04-11 |
| 179 | Largest Number | 🟡 Medium | Arrays |
2026-04-27 |
| 190 | Reverse Bits | 🟢 Easy | BitManipulation |
2026-05-09 |
| 191 | Number of 1 Bits | 🟢 Easy | BitManipulation |
2026-05-20 |
| 202 | Happy Number | 🟢 Easy | TwoPointers |
2026-04-29 |
| 204 | Count Primes | 🟡 Medium | Numbers |
2026-07-15 |
| 205 | Isomorphic Strings | 🟢 Easy | Misc |
2026-04-20 |
| 217 | Contains Duplicate | 🟢 Easy | Arrays |
2026-04-06 |
| 219 | Contains Duplicate II | 🟢 Easy | SlidingWindow |
2026-06-04 |
| 231 | Power of Two | 🟢 Easy | BitManipulation |
2026-04-19 |
| 240 | Search a 2D Matrix II | 🟡 Medium | Arrays |
2026-04-24 |
| 242 | Valid Anagram | 🟢 Easy | Misc |
2026-04-21 |
| 258 | Add Digits | 🟢 Easy | Maths |
2026-04-08 |
| 263 | Ugly Number | 🟢 Easy | Numbers |
2026-04-17 |
| 268 | Missing Number | 🟢 Easy | Arrays |
2026-04-14 |
| 283 | Move Zeroes | 🟢 Easy | TwoPointers |
2026-05-10 |
| 287 | Find the Duplicate Number | 🟡 Medium | Arrays |
2026-04-15 |
| 292 | Nim Game | 🟢 Easy | Maths |
2026-06-05 |
| 316 | Remove Duplicate Letters | 🟡 Medium | Greedy |
2026-07-19 |
| 338 | Counting Bits | 🟢 Easy | DynamicProgramming |
2026-07-23 |
| 344 | Reverse String | 🟢 Easy | TwoPointers |
2026-05-08 |
| 349 | Intersection of Two Arrays | 🟢 Easy | Arrays |
2026-05-29 |
| 350 | Intersection of Two Arrays II | 🟢 Easy | Arrays |
2026-05-18 |
| 367 | Valid Perfect Square | 🟢 Easy | Numbers |
2026-04-08 |
| 374 | Guess Number Higher or Lower | 🟢 Easy | BinarySearch |
2026-04-29 |
| 383 | Ransom Note | 🟢 Easy | Strings |
2026-05-05 |
| 387 | First Unique Character in a String | 🟢 Easy | Strings |
2026-05-27 |
| 389 | Find the Difference | 🟢 Easy | Strings |
2026-04-27 |
| 410 | Split Array Largest Sum | 🔴 Hard | Arrays |
2026-04-09 |
| 412 | Fizz Buzz | 🟢 Easy | Maths |
2026-05-13 |
| 414 | Third Maximum Number | 🟢 Easy | Arrays |
2026-07-06 |
| 415 | Add Strings | 🟢 Easy | Strings |
2026-07-19 |
| 442 | Find All Duplicates in an Array | 🟡 Medium | Arrays |
2026-04-15 |
| 448 | Find All Numbers Disappeared in an Array | 🟢 Easy | Arrays |
2026-04-14 |
| 455 | Assign Cookies | 🟢 Easy | Greedy |
2026-05-29 |
| 485 | Max Consecutive Ones | 🟢 Easy | Arrays |
2026-06-14 |
| 506 | Relative Ranks | 🟢 Easy | Arrays |
2026-07-06 |
| 509 | Fibonacci Number | 🟢 Easy | DynamicProgramming |
2026-06-10 |
| 557 | Reverse Words in a String III | 🟢 Easy | Strings |
2026-05-21 |
| 628 | Maximum Product of Three Numbers | 🟢 Easy | Arrays |
2026-05-30 |
| 645 | Set Mismatch | 🟢 Easy | Arrays |
2026-04-16 |
| 704 | Binary Search | 🟢 Easy | BinarySearch |
2026-04-07 |
| 709 | To Lower Case | 🟢 Easy | Strings |
2026-05-21 |
| 724 | Find Pivot Index | 🟢 Easy | PrefixSum |
2026-06-07 |
| 744 | Find Smallest Letter Greater Than Target | 🟢 Easy | BinarySearch |
2026-04-02 |
| 796 | Rotate String | 🟢 Easy | Strings |
2026-05-03 |
| 852 | Peak Index in a Mountain Array | 🟡 Medium | BinarySearch |
2026-04-03 |
| 976 | Largest Perimeter Triangle | 🟢 Easy | Arrays |
2026-05-30 |
| 977 | Squares of a Sorted Array | 🟢 Easy | Arrays |
2026-05-29 |
| 1051 | Height Checker | 🟢 Easy | Arrays |
2026-06-03 |
| 1071 | Greatest Common Divisor of Strings | 🟢 Easy | Strings |
2026-07-14 |
| 1081 | Smallest Subsequence of Distinct Characters | 🟡 Medium | Greedy |
2026-07-19 |
| 1095 | Find in Mountain Array | 🔴 Hard | BinarySearch |
2026-04-04 |
| 1189 | Maximum Number of Balloons | 🟢 Easy | Strings |
2026-06-22 |
| 1260 | Shift 2D Grid | 🟢 Easy | Arrays |
2026-07-20 |
| 1288 | Remove Covered Intervals | 🟡 Medium | Arrays |
2026-07-06 |
| 1291 | Sequential Digits | 🟡 Medium | Enum |
2026-07-14 |
| 1295 | Find Numbers with Even Number of Digits | 🟢 Easy | Numbers |
2026-03-26 |
| 1301 | Number of Paths with Max Score | 🔴 Hard | Arrays |
2026-07-06 |
| 1331 | Rank Transform of an Array | 🟢 Easy | Arrays |
2026-07-14 |
| 1337 | The K Weakest Rows in a Matrix | 🟢 Easy | Arrays |
2026-05-25 |
| 1342 | Number of Steps to Reduce a Number to Zero | 🟢 Easy | BitManipulation |
2026-05-31 |
| 1344 | Angle Between Hands of a Clock | 🟡 Medium | Maths |
2026-06-18 |
| 1346 | Check If N and Its Double Exist | 🟢 Easy | Numbers |
2026-04-16 |
| 1351 | Count Negative Numbers in a Sorted Matrix | 🟢 Easy | Arrays |
2026-05-22 |
| 1358 | Number of Substrings Containing All Three Characters | 🟡 Medium | SlidingWindow |
2026-06-30 |
| 1365 | How Many Numbers Are Smaller Than the Current Number | 🟢 Easy | Misc |
2026-04-11 |
| 1662 | Check If Two String Arrays are Equivalent | 🟢 Easy | Strings |
2026-05-21 |
| 1665 | Minimum Initial Energy to Finish Tasks | 🔴 Hard | Greedy |
2026-05-12 |
| 1668 | Maximum Repeating Substring | 🟢 Easy | Strings |
2026-05-24 |
| 1672 | Richest Customer Wealth | 🟢 Easy | Misc |
2026-03-26 |
| 1732 | Find the Highest Altitude | 🟢 Easy | PrefixSum |
2026-06-19 |
| 1752 | Check if Array Is Sorted and Rotated | 🟢 Easy | Arrays |
2026-05-23 |
| 1833 | Maximum Ice Cream Bars | 🟡 Medium | Arrays |
2026-06-23 |
| 1840 | Maximum Building Height | 🔴 Hard | Arrays |
2026-06-20 |
| 1846 | Maximum Element After Decreasing and Rearranging | 🟡 Medium | Greedy |
2026-06-29 |
| 1952 | Three Divisors | 🟢 Easy | Enum |
2026-07-14 |
| 1967 | Number of Strings That Appear as Substrings in Word | 🟢 Easy | Strings |
2026-05-21 |
| 1979 | Find Greatest Common Divisor of Array | 🟢 Easy | Arrays |
2026-07-14 |
| 1991 | Find the Middle Index in Array | 🟢 Easy | PrefixSum |
2026-06-07 |
| 2095 | Delete the Middle Node of a Linked List | 🟡 Medium | LinkedList |
2026-06-15 |
| 2114 | Maximum Number of Words Found in Sentences | 🟢 Easy | Strings |
2026-04-16 |
| 2126 | Destroying Asteroids | 🟡 Medium | Greedy |
2026-05-31 |
| 2129 | Capitalize the Title | 🟢 Easy | Strings |
2026-05-21 |
| 2130 | Maximum Twin Sum of a Linked List | 🟡 Medium | LinkedList |
2026-06-14 |
| 2144 | Minimum Cost of Buying Candies With Discount | 🟢 Easy | Greedy |
2026-06-01 |
| 2161 | Partition Array According to Given Pivot | 🟡 Medium | Arrays |
2026-06-08 |
| 2196 | Create Binary Tree From Descriptions | 🟡 Medium | Tree |
2026-06-07 |
| 2287 | Rearrange Characters to Make Target String | 🟢 Easy | Strings |
2026-06-22 |
| 2299 | Strong Password Checker II | 🟢 Easy | Strings |
2026-06-02 |
| 2413 | Smallest Even Multiple | 🟢 Easy | Numbers |
2026-07-14 |
| 2450 | Number of Distinct Binary Strings After Applying Operations | 🟡 Medium | Arrays |
2026-05-20 |
| 2492 | Minimum Score of a Path Between Two Cities | 🟡 Medium | Graphs |
2026-07-06 |
| 2553 | Separate the Digits in an Array | 🟢 Easy | Arrays |
2026-05-11 |
| 2670 | Find the Distinct Difference Array | 🟢 Easy | Arrays |
2026-06-07 |
| 2685 | Count the Number of Complete Components | 🟡 Medium | Graphs |
2026-07-14 |
| 2754 | Bind Function to Context | 🟡 Medium | PrefixSum |
2026-06-07 |
| 2784 | Check if Array is Good | 🟢 Easy | Arrays |
2026-05-20 |
| 2812 | Find the Safest Path in a Grid | 🟡 Medium | Arrays |
2026-07-01 |
| 3020 | Find the Maximum Number of Elements in Subset | 🟡 Medium | Arrays |
2026-06-27 |
| 3074 | Apple Redistribution into Boxes | 🟢 Easy | Arrays |
2026-05-22 |
| 3120 | Count the Number of Special Characters I | 🟢 Easy | Strings |
2026-05-26 |
| 3286 | Find a Safe Walk Through a Grid | 🟡 Medium | Arrays |
2026-07-04 |
| 3300 | Minimum Element After Replacement With Digit Sum | 🟢 Easy | Arrays |
2026-05-29 |
| 3312 | Sorted GCD Pair Queries | 🔴 Hard | Numbers |
2026-07-17 |
| 3336 | Find the Number of Subsequences With Equal GCD | 🔴 Hard | DynamicProgramming |
2026-07-14 |
| 3411 | Maximum Subarray With Equal Products | 🟢 Easy | SlidingWindow |
2026-07-14 |
| 3499 | Maximize Active Section with Trade I | 🟡 Medium | Strings |
2026-07-21 |
| 3513 | Number of Unique XOR Triplets I | 🟡 Medium | BitManipulation |
2026-07-23 |
| 3514 | Number of Unique XOR Triplets II | 🟡 Medium | BitManipulation |
2026-07-24 |
| 3532 | Path Existence Queries in a Graph I | 🟡 Medium | Graphs |
2026-07-14 |
| 3534 | Path Existence Queries in a Graph II | 🔴 Hard | Graphs |
2026-07-14 |
| 3558 | Number of Ways to Assign Edge Weights I | 🟡 Medium | Tree |
2026-06-12 |
| 3612 | Process String with Special Operations I | 🟡 Medium | Strings |
2026-06-16 |
| 3614 | Process String with Special Operations II | 🔴 Hard | Strings |
2026-06-17 |
| 3620 | Network Recovery Pathways | 🔴 Hard | Arrays |
2026-07-04 |
| 3633 | Earliest Finish Time for Land and Water Rides I | 🟢 Easy | Arrays |
2026-06-02 |
| 3636 | Threshold Majority Queries | 🔴 Hard | Arrays |
2026-06-03 |
| 3658 | GCD of Odd and Even Sums | 🟢 Easy | Numbers |
2026-07-15 |
| 3689 | Maximum Total Subarray Value I | 🟡 Medium | Greedy |
2026-06-09 |
| 3699 | Number of ZigZag Arrays I | 🔴 Hard | DynamicProgramming |
2026-06-23 |
| 3700 | Number of ZigZag Arrays II | 🔴 Hard | DynamicProgramming |
2026-06-25 |
| 3737 | Count Subarrays With Majority Element I | 🟡 Medium | PrefixSum |
2026-06-25 |
| 3739 | Count Subarrays With Majority Element II | 🔴 Hard | PrefixSum |
2026-06-26 |
| 3751 | Total Waviness of Numbers in Range I | 🟡 Medium | Numbers |
2026-06-04 |
| 3753 | Total Waviness of Numbers in Range II | 🔴 Hard | Unsolved |
2026-06-05 |
| 3754 | Concatenate Non-Zero Digits and Multiply by Sum I | 🟢 Easy | Maths |
2026-07-08 |
| 3756 | Concatenate Non-Zero Digits and Multiply by Sum II | 🟡 Medium | PrefixSum |
2026-07-08 |
| 3783 | Mirror Distance of an Integer | 🟢 Easy | Strings |
2026-04-17 |
| 3838 | Weighted Word Mapping | 🟢 Easy | Strings |
2026-06-13 |
| 3867 | Sum of GCD of Formed Pairs | 🟡 Medium | Numbers |
2026-07-16 |
| 3941 | Password Strength | 🟡 Medium | Strings |
2026-06-02 |
| 3945 | Digit Frequency Score | 🟢 Easy | Numbers |
2026-06-04 |
| 3950 | Exactly One Consecutive Set Bits Pair | 🟢 Easy | Numbers |
2026-06-07 |
| 3951 | Minimum Energy to Maintain Brightness | 🟡 Medium | Greedy |
2026-06-07 |
| 3954 | Sum of Compatible Numbers in Range I | 🟢 Easy | Numbers |
2026-06-07 |
| 3955 | Valid Binary Strings With Cost Limit | 🟡 Medium | Numbers |
2026-06-07 |
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