January 2026

What's Changed

Problem Solved

• Problem 66. Plus One Without Using Reverse (Improved and in C)
• Problem 85. Maximal Rectangle
• Problem 106. Construct Binary Tree from Inorder and Postorder Traversal
• Problem 199. Binary Tree Right Side View
• Problem 208. Implement Trie (Prefix Tree)
• Problem 225. Implement Stack using Queues
• Problem 227. Basic Calculator II
• Problem 235. Lowest Common Ancestor of a Binary Search Tree
• Problem 429. N-ary Tree Level Order Traversal
• Problem 508. Most Frequent Subtree Sum
• Problem 537. Complex Number Multiplication
• Problem 559. Maximum Depth of N-ary Tree
• Problem 575. Distribute Candies
• Problem 589. N-ary Tree Preorder Traversal
• Problem 690. Employee Importance
• Problem 712. Minimum ASCII Delete Sum for Two Strings
• Problem 714. Best Time to Buy and Sell Stock with Transaction Fee (in C)
• Problem 766. Toeplitz Matrix
• Problem 806. Number of Lines To Write String (in C)
• Problem 824. Goat Latin
• Problem 922. Sort Array By Parity II (in C)
• Problem 946. Validate Stack Sequences
• Problem 955. Delete Columns to Make Sorted II (in C)
• Problem 986. Interval List Intersections
• Problem 998. Maximum Binary Tree II
• Problem 999. Available Captures for Rook (in C)
• Problem 1020. Number of Enclaves
• Problem 1030. Matrix Cells in Distance Order
• Problem 1161. Maximum Level Sum of a Binary Tree
• Problem 1200. Minimum Absolute Difference
• Problem 1237. Find Positive Integer Solution for a Given Equation
• Problem 1339. Maximum Product of Splitted Binary Tree
• Problem 1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold (in C)
• Problem 1385. Find the Distance Value Between Two Arrays
• Problem 1387. Sort Integers by The Power Value (in C)
• Problem 1390. Four Divisors
• Problem 1411. Number of Ways to Paint N × 3 Grid
• Problem 1433. Check If a String Can Break Another String
• Problem 1458. Max Dot Product of Two Subsequences (Modified)
• Problem 1492. The kth Factor of n
• Problem 1502. Can Make Arithmetic Progression From Sequence
• Problem 1619. Mean of Array After Removing Some Elements (in C)
• Problem 1721. Swapping Nodes in a Linked List
• Problem 1779. Find Nearest Point That Has the Same X or Y Coordinate
• Problem 1970. Last Day Where You Can Still Cross
• Problem 1975. Maximum Matrix Sum (in C)
• Problem 1991. Find the Middle Index in Array
• Problem 2024. Maximize the Confusion of an Exam
• Problem 2136. Earliest Possible Day of Full Bloom
• Problem 2180. Count Integers With Even Digit Sum
• Problem 2303. Calculate Amount Paid in Taxes
• Problem 2305. Fair Distribution of Cookies
• Problem 2309. Greatest English Letter in Upper and Lower Case (in C)
• Problem 2350. Shortest Impossible Sequence of Rolls
• Problem 2352. Equal Row and Column Pairs
• Problem 2399. Check Distances Between Same Letters (in C)
• Problem 2483. Minimum Penalty for a Shop
• Problem 2527. Find Xor-Beauty of Array
• Problem 2536. Increment Submatrices by One (in C)
• Problem 2562. Find the Array Concatenation Value (in C)
• Problem 2639. Find the Width of Columns of a Grid
• Problem 2895. Minimum Processing Time
• Problem 2980. Check if Bitwise OR Has Trailing Zeros
• Problem 3033. Modify the Matrix
• Problem 3069. Distribute Elements Into Two Arrays I
• Problem 3074. Apple Redistribution into Boxes (in C)
• Problem 3208. Alternating Groups II
• Problem 3452. Sum of Good Numbers
• Problem 3483. Unique 3-Digit Even Numbers
• Problem 3536. Maximum Product of Two Digits
• Problem 3537. Fill a Special Grid
• Problem 3573. Best Time to Buy and Sell Stock V (in C)
• Problem 3578. Count Partitions With Max-Min Difference at Most K
• Problem 3606. Coupon Code Validator (in C)
• Problem 3652. Best Time to Buy and Sell Stock using Strategy (in C)
• Problem 3653. XOR After Range Multiplication Queries I
• Problem 3663. Find The Least Frequent Digit
• Problem 3708. Longest Fibonacci Subarray
• Problem 3746. Minimum String Length After Balanced Removals
• Problem 3751. Total Waviness of Numbers in Range I
• Problem 3760. Maximum Substrings With Distinct Start
• Problem 3783. Mirror Distance of an Integer
• Problem 3794. Reverse String Prefix
• Problem 3798. Largest Even Number

Other Changes

• Updated Lefthook configuration
• Upgraded development dependencies

Full Changelog: 202512...202601

December 2025

What's Changed

Problem Solved

• Problem 93. Restore IP Addresses
• Problem 102. Binary Tree Level Order Traversal
• Problem 216. Combination Sum III
• Problem 222. Count Complete Tree Nodes
• Problem 496. Next Greater Element I
• Problem 500. Keyboard Row
• Problem 538. Convert BST to Greater Tree
• Problem 714. Best Time to Buy and Sell Stock with Transaction Fee
• Problem 732. My Calendar III
• Problem 762. Prime Number of Set Bits in Binary Representation
• Problem 806. Number of Lines To Write String
• Problem 814. Binary Tree Pruning
• Problem 821. Shortest Distance to a Character
• Problem 841. Keys and Rooms
• Problem 869. Reordered Power of 2
• Problem 892. Surface Area of 3D Shapes
• Problem 893. Groups of Special-Equivalent Strings
• Problem 904. Fruit Into Baskets
• Problem 922. Sort Array By Parity II
• Problem 955. Delete Columns to Make Sorted II
• Problem 965. Univalued Binary Tree
• Problem 969. Pancake Sorting
• Problem 999. Available Captures for Rook
• Problem 1011. Capacity To Ship Packages Within D Days
• Problem 1015. Smallest Integer Divisible by K (in C)
• Problem 1018. Binary Prefix Divisible By 5 (in C)
• Problem 1111. Maximum Nesting Depth of Two Valid Parentheses Strings
• Problem 1217. Minimum Cost to Move Chips to The Same Position
• Problem 1222. Queens That Can Attack the King
• Problem 1286. Iterator for Combination
• Problem 1310. XOR Queries of a Subarray (in C)
• Problem 1318. Minimum Flips to Make a OR b Equal to c
• Problem 1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
• Problem 1387. Sort Integers by The Power Value
• Problem 1523. Count Odd Numbers in an Interval Range
• Problem 1619. Mean of Array After Removing Some Elements
• Problem 1638. Count Substrings That Differ by One Character
• Problem 1706. Where Will the Ball Fall
• Problem 1765. Map of Highest Peak
• Problem 1769. Minimum Number of Operations to Move All Balls to Each Box
• Problem 1781. Sum of Beauty of All Substrings
• Problem 1860. Incremental Memory Leak
• Problem 1920. Build Array from Permutation (in C)
• Problem 1925. Count Square Sum Triples
• Problem 2042. Check if Numbers Are Ascending in a Sentence
• Problem 2043. Simple Bank System
• Problem 2054. Two Best Non-Overlapping Events
• Problem 2057. Smallest Index With Equal Value
• Problem 2062. Count Vowel Substrings of a String
• Problem 2070. Most Beautiful Item for Each Query (in C)
• Problem 2110. Number of Smooth Descent Periods of a Stock
• Problem 2141. Maximum Running Time of N Computers
• Problem 2191. Sort the Jumbled Numbers
• Problem 2283. Check if Number Has Equal Digit Count and Digit Value
• Problem 2309. Greatest English Letter in Upper and Lower Case
• Problem 2357. Make Array Zero by Subtracting Equal Amounts (in C)
• Problem 2389. Longest Subsequence With Limited Sum
• Problem 2399. Check Distances Between Same Letters
• Problem 2416. Sum of Prefix Scores of Strings (in C)
• Problem 2435. Paths in Matrix Whose Sum Is Divisible by K (in C)
• Problem 2475. Number of Unequal Triplets in Array
• Problem 2506. Count Pairs Of Similar Strings
• Problem 2536. Increment Submatrices by One
• Problem 2554. Maximum Number of Integers to Choose From a Range I (updated)
• Problem 2562. Find the Array Concatenation Value
• Problem 2578. Split With Minimum Sum
• Problem 2595. Number of Even and Odd Bits
• Problem 2640. Find the Score of All Prefixes of an Array
• Problem 2848. Points That Intersect With Cars
• Problem 2917. Find the K-or of an Array
• Problem 2924. Find Champion II (in C)
• Problem 2940. Find Building Where Alice and Bob Can Meet
• Problem 3074. Apple Redistribution into Boxes
• Problem 3159. Find Occurrences of an Element in an Array
• Problem 3274. Check if Two Chessboard Squares Have the Same Color
• problem 3381. Maximum Subarray Sum With Length Divisible by K
• Problem 3402. Minimum Operations to Make Columns Strictly Increasing
• Problem 3531. Count Covered Buildings
• Problem 3545. Minimum Deletions for At Most K Distinct Characters
• Problem 3573. Best Time to Buy and Sell Stock V
• Problem 3577. Count the Number of Computer Unlocking Permutations
• Problem 3583. Count Special Triplets
• Problem 3606. Coupon Code Validator
• Problem 3652. Best Time to Buy and Sell Stock using Strategy
• Problem 3745. Maximize Expression of Three Elements
• Problem 3750. Minimum Number of Flips to Reverse Binary String

Other Changes

• Upgraded development dependencies

Full Changelog: 202511...202512

November 2025

What's Changed

Problem Solved

• Solve Problem 166. Fraction to Recurring Decimal
• Solve Problem 173. Binary Search Tree Iterator
• Solve Problem 230. Kth Smallest Element in a BST
• Solve Problem 417. Pacific Atlantic Water Flow
• Solve Problem 474. Ones and Zeroes
• Solve Problem 637. Average of Levels in Binary Tree
• Solve Problem 695. Max Area of Island
• Solve Problem 717. 1-bit and 2-bit Characters
• Solve Problem 757. Set Intersection Size At Least Two
• Solve Problem 778. Swim in Rising Water
• Solve Problem 784. Letter Case Permutation
• Solve Problem 811. Subdomain Visit Count
• Solve Problem 883. Projection Area of 3D Shapes
• Solve Problem 890. Find and Replace Pattern
• Solve Problem 930. Binary Subarrays With Sum (in C)
• Solve Problem 944. Delete Columns to Make Sorted
• Solve Problem 1015. Smallest Integer Divisible by K
• Solve Problem 1018. Binary Prefix Divisible By 5
• Solve Problem 1022. Sum of Root To Leaf Binary Numbers
• Solve Problem 1104. Path In Zigzag Labelled Binary Tree
• Solve Problem 1262. Greatest Sum Divisible by Three
• Solve Problem 1396. Design Underground System
• Solve Problem 1403. Minimum Subsequence in Non-Increasing Order
• Solve Problem 1418. Display Table of Food Orders in a Restaurant
• Solve Problem 1448. Count Good Nodes in Binary Tree
• Solve Problem 1450. Number of Students Doing Homework at a Given Time
• Solve Problem 1526. Minimum Number of Increments on Subarrays to Form a Target Array
• Solve Problem 1529. Minimum Suffix Flips
• Solve Problem 1625. Lexicographically Smallest String After Applying Operations
• Solve Problem 1710. Maximum Units on a Truck
• Solve Problem 1742. Maximum Number of Balls in a Box
• Solve Problem 1833. Maximum Ice Cream Bars
• Solve Problem 1880. Check if Word Equals Summation of Two Words
• Solve Problem 1884. Egg Drop With 2 Eggs and N Floors
• Solve Problem 2023. Number of Pairs of Strings With Concatenation Equal to Target
• Solve Problem 2048. Next Greater Numerically Balanced Number
• Solve Problem 2154. Keep Multiplying Found Values by Two
• Solve Problem 2169. Count Operations to Obtain Zero
• Solve Problem 2255. Count Prefixes of a Given String
• Solve Problem 2300. Successful Pairs of Spells and Potions (in C)
• Solve Problem 2341. Maximum Number of Pairs in Array
• Solve Problem 2357. Make Array Zero by Subtracting Equal Amounts
• Solve Problem 2363. Merge Similar Items (in C)
• Solve Problem 2428. Maximum Sum of an Hourglass (in C)
• Solve Problem 2435. Paths in Matrix Whose Sum Is Divisible by K
• Solve Problem 2496. Maximum Value of a String in an Array
• Solve Problem 2528. Maximize the Minimum Powered City
• Solve Problem 2586. Count the Number of Vowel Strings in Range
• Solve Problem 2598. Smallest Missing Non-negative Integer After Operations (in C)
• Solve Problem 2643. Row With Maximum Ones
• Solve Problem 2651. Calculate Delayed Arrival Time
• Solve Problem 2654. Minimum Number of Operations to Make All Array Elements Equal to 1
• Solve Problem 2788. Split Strings by Separator
• Solve Problem 2928. Distribute Candies Among Children I
• Solve Problem 2932. Maximum Strong Pair XOR I
• Solve Problem 2951. Find the Peaks
• Solve Problem 3028. Ant on the Boundary
• Solve Problem 3079. Find the Sum of Encrypted Integers
• Solve Problem 3147. Taking Maximum Energy From the Mystic Dungeon (in C)
• Solve Problem 3186. Maximum Total Damage With Spell Casting (in C)
• Solve Problem 3190. Find Minimum Operations to Make All Elements Divisible by Three (in C)
• Solve Problem 3228. Maximum Number of Operations to Move Ones to the End
• Solve Problem 3239. Minimum Number of Flips to Make Binary Grid Palindromic I
• Solve Problem 3314. Construct the Minimum Bitwise Array I
• Solve Problem 3318. Find X-Sum of All K-Long Subarrays I
• Solve Problem 3346. Maximum Frequency of an Element After Performing Operations I
• Solve Problem 3347. Maximum Frequency of an Element After Performing Operations II
• Solve Problem 3349. Adjacent Increasing Subarrays Detection I (in C)
• Solve Problem 3350. Adjacent Increasing Subarrays Detection II (in C)
• Solve Problem 3354. Make Array Elements Equal to Zero
• Solve Problem 3397. Maximum Number of Distinct Elements After Operations
• Solve Problem 3432. Count Partitions with Even Sum Difference
• Solve Problem 3439. Reschedule Meetings for Maximum Free Time I (in C)
• Solve Problem 3440. Reschedule Meetings for Maximum Free Time II (in C)
• Solve Problem 3487. Maximum Unique Subarray Sum After Deletion
• Solve Problem 3492. Maximum Containers on a Ship
• Solve Problem 3494. Find the Minimum Amount of Time to Brew Potions (in C)
• Solve Problem 3527. Find the Most Common Response
• Solve Problem 3542. Minimum Operations to Convert All Elements to Zero
• Solve Problem 3684. Maximize Sum of At Most K Distinct Elements
• Solve Problem 3701. Compute Alternating Sum (in C)
• Solve Problem 3712. Sum of Elements With Frequency Divisible by K
• Solve Problem 3726. Remove Zeros in Decimal Representation
• Solve Problem 3731. Find Missing Elements
• Solve Problem 3736. Minimum Moves to Equal Array Elements III

Other Changes

• Use self-hosted runner in GitHub workflow
• Upgraded development dependencies

Full Changelog: 202510...202511

October 2025

What's Changed

Problem Solved

• Problem 97. Interleaving String (in C)
• Problem 213. House Robber II
• Problem 407. Trapping Rain Water II (in C)
• Problem 419. Battleships in a Board
• Problem 461. Hamming Distance
• Problem 498. Diagonal Traverse (in C)
• Problem 930. Binary Subarrays With Sum Using Sliding Window
• Problem 950. Reveal Cards In Increasing Order
• Problem 961. N-Repeated Element in Size 2N Array (in C)
• Problem 966. Vowel Spellchecker
• Problem 1039. Minimum Score Triangulation of Polygon
• Problem 1304. Find N Unique Integers Sum up to Zero
• Problem 1314. Matrix Block Sum
• Problem 1317. Convert Integer to the Sum of Two No-Zero Integers
• Problem 1332. Remove Palindromic Subsequences
• Problem 1370. Increasing Decreasing String
• Problem 1402. Reducing Dishes
• Problem 1488. Avoid Flood in The City
• Problem 1493. Longest Subarray of 1's After Deleting One Element (in C)
• Problem 1733. Minimum Number of People to Teach
• Problem 1751. Maximum Number of Events That Can Be Attended II (in C)
• Problem 1935. Maximum Number of Words You Can Type
• Problem 2032. Two Out of Three
• Problem 2089. Find Target Indices After Sorting Array
• Problem 2099. Find Subsequence of Length K With the Largest Sum (in C)
• Problem 2300. Successful Pairs of Spells and Potions
• Problem 2327. Number of People Aware of a Secret
• Problem 2363. Merge Similar Items
• Problem 2428. Maximum Sum of an Hourglass
• Problem 2598. Smallest Missing Non-negative Integer After Operations
• Problem 2670. Find the Distinct Difference Array
• Problem 2733. Neither Minimum nor Maximum
• Problem 3000. Maximum Area of Longest Diagonal Rectangle (in C)
• Problem 3021. Alice and Bob Playing Flower Game (in C)
• Problem 3025. Find the Number of Ways to Place People I (in C)
• Problem 3027. Find the Number of Ways to Place People II (in C)
• Problem 3100. Water Bottles II
• Problem 3147. Taking Maximum Energy From the Mystic Dungeon
• Problem 3184. Count Pairs That Form a Complete Day I (in C)
• Problem 3186. Maximum Total Damage With Spell Casting
• Problem 3195. Find the Minimum Area to Cover All Ones I (in C)
• Problem 3227. Vowels Game in a String
• Problem 3242. Design Neighbor Sum Service
• Problem 3304. Find the K-th Character in String Game I (in C)
• Problem 3307. Find the K-th Character in String Game II (in C)
• Problem 3349. Adjacent Increasing Subarrays Detection I
• Problem 3350. Adjacent Increasing Subarrays Detection II
• Problem 3370. Smallest Number With All Set Bits
• Problem 3408. Design Task Manager
• Problem 3439. Reschedule Meetings for Maximum Free Time I
• Problem 3440. Reschedule Meetings for Maximum Free Time II
• Problem 3446. Sort Matrix by Diagonals
• Problem 3461. Check If Digits Are Equal in String After Operations I
• Problem 3484. Design Spreadsheet
• Problem 3494. Find the Minimum Amount of Time to Brew Potions
• Problem 3508. Implement Router
• Problem 3602. Hexadecimal and Hexatrigesimal Conversion (in C)
• Problem 3658. GCD of Odd and Even Sums
• Problem 3668. Restore Finishing Order
• Problem 3683. Earliest Time to Finish One Task
• Problem 3688. Bitwise OR of Even Numbers in an Array
• Problem 3701. Compute Alternating Sum

Other Changes

• Upgraded development dependencies

Full Changelog: 202509...202510

September 2025

What's Changed

Problem Solved

• Problem 97. Interleaving String
• Problem 367. Valid Perfect Square (in C)
• Problem 494. Target Sum (in C)
• Problem 498. Diagonal Traverse
• Problem 605. Can Place Flowers (in C)
• Problem 679. 24 Game
• Problem 898. Bitwise ORs of Subarrays
• Problem 961. N-Repeated Element in Size 2N Array
• Problem 1493. Longest Subarray of 1's After Deleting One Element
• Problem 1498. Number of Subsequences That Satisfy the Given Sum Condition
• Problem 1641. Count Sorted Vowel Strings (in C)
• Problem 1751. Maximum Number of Events That Can Be Attended II
• Problem 1770. Maximum Score from Performing Multiplication Operations (in C)
• Problem 1941. Check if All Characters Have Equal Number of Occurrences (in C)
• Problem 2115. Find All Possible Recipes from Given Supplies
• Problem 2182. Construct String With Repeat Limit (in C)
• Problem 2210. Count Hills and Valleys in an Array (in C)
• Problem 2211. Count Collisions on a Road (in C)
• Problem 2402. Meeting Rooms III
• Problem 2411. Smallest Subarrays With Maximum Bitwise OR
• Problem 2419. Longest Subarray With Maximum Bitwise AND (Improved)
• Problem 2500. Delete Greatest Value in Each Row (in C)
• Problem 2716. Minimize String Length
• Problem 2762. Continuous Subarrays (in C)
• Problem 3000. Maximum Area of Longest Diagonal Rectangle
• Problem 3005. Count Elements With Maximum Frequency (in C)
• Problem 3021. Alice and Bob Playing Flower Game
• Problem 3025. Find the Number of Ways to Place People I
• Problem 3027. Find the Number of Ways to Place People II
• Problem 3170. Lexicographically Minimum String After Removing Stars (in C)
• Problem 3184. Count Pairs That Form a Complete Day I
• Problem 3195. Find the Minimum Area to Cover All Ones I
• Problem 3201. Find the Maximum Length of Valid Subsequence I (in C)
• Problem 3202. Find the Maximum Length of Valid Subsequence II (in C)
• Problem 3304. Find the K-th Character in String Game I
• Problem 3307. Find the K-th Character in String Game II
• Problem 3405. Count the Number of Arrays with K Matching Adjacent Elements
• Problem 3477. Fruits Into Baskets II
• Problem 3602. Hexadecimal and Hexatrigesimal Conversion

Full Changelog: 202508...202509

August 2025

What's Changed

Problem Solved

• Problem 135. Candy (in C)
• Problem 594. Longest Harmonious Subsequence
• Problem 617. Merge Two Binary Trees
• Problem 894. All Possible Full Binary Trees
• Problem 897. Increasing Order Search Tree
• Problem 1061. Lexicographically Smallest Equivalent String
• Problem 1252. Cells with Odd Values in a Matrix (in C)
• Problem 1298. Maximum Candies You Can Get from Boxes
• Problem 1351. Count Negative Numbers in a Sorted Matrix
• Problem 1374. Generate a String With Characters That Have Odd Counts
• Problem 1394. Find Lucky Integer in an Array
• Problem 1432. Max Difference You Can Get From Changing an Integer
• Problem 1472. Design Browser History
• Problem 1695. Maximum Erasure Value
• Problem 1725. Number Of Rectangles That Can Form The Largest Square (in C)
• Problem 1748. Sum of Unique Elements (in C)
• Problem 1812. Determine Color of a Chessboard Square (in C)
• Problem 1837. Sum of Digits in Base K
• Problem 1865. Finding Pairs With a Certain Sum
• Problem 1941. Check if All Characters Have Equal Number of Occurrences
• Problem 1974. Minimum Time to Type Word Using Special Typewriter
• Problem 2016. Maximum Difference Between Increasing Elements
• Problem 2081. Sum of k-Mirror Numbers
• Problem 2099. Find Subsequence of Length K With the Largest Sum
• Problem 2138. Divide a String Into Groups of Size k
• Problem 2200. Find All K-Distant Indices in an Array
• Problem 2210. Count Hills and Valleys in an Array
• Problem 2221. Find Triangular Sum of an Array (in C)
• Problem 2294. Partition Array Such That Maximum Difference Is K
• Problem 2311. Longest Binary Subsequence Less Than or Equal to K
• Problem 2317. Maximum XOR After Operations (in C)
• Problem 2359. Find Closest Node to Given Two Nodes (in C)
• Problem 2390. Removing Stars From a String
• Problem 2405. Optimal Partition of String
• Problem 2410. Maximum Matching of Players With Trainers
• Problem 2434. Using a Robot to Print the Lexicographically Smallest String
• Problem 2553. Separate the Digits in an Array (in C)
• Problem 2566. Maximum Difference by Remapping a Digit
• Problem 2697. Lexicographically Smallest Palindrome (in C)
• Problem 2710. Remove Trailing Zeros From a String
• Problem 2913. Subarrays Distinct Element Sum of Squares I (in C)
• Problem 2960. Count Tested Devices After Test Operations
• Problem 3019. Number of Changing Keys (in C)
• Problem 3085. Minimum Deletions to Make String K-Special
• Problem 3136. Valid Word
• Problem 3168. Minimum Number of Chairs in a Waiting Room
• Problem 3170. Lexicographically Minimum String After Removing Stars
• Problem 3201. Find the Maximum Length of Valid Subsequence I
• Problem 3202. Find the Maximum Length of Valid Subsequence II
• Problem 3258. Count Substrings That Satisfy K-Constraint I
• Problem 3324. Find the Sequence of Strings Appeared on the Screen (in C)
• Problem 3330. Find the Original Typed String I
• Problem 3362. Zero Array Transformation III (in C)
• Problem 3403. Find the Lexicographically Largest String From the Box I
• Problem 3423. Maximum Difference Between Adjacent Elements in a Circular Array
• Problem 3442. Maximum Difference Between Even and Odd Frequency I
• Problem 3445. Maximum Difference Between Even and Odd Frequency II
• Problem 3541. Find Most Frequent Vowel and Consonant (in C)

Other Changes

• Updated development dependencies

Full Changelog: 202507...202508

July 2025

What's Changed

Problem Solved

• Problem 135. Candy
• Problem 561. Array Partition (in C)
• Problem 728. Self Dividing Numbers
• Problem 942. DI String Match
• Problem 1252. Cells with Odd Values in a Matrix
• Problem 1641. Count Sorted Vowel Strings
• Problem 1725. Number Of Rectangles That Can Form The Largest Square
• Problem 1748. Sum of Unique Elements
• Problem 1812. Determine Color of a Chessboard Square
• Problem 1817. Finding the Users Active Minutes (in C)
• Problem 1827. Minimum Operations to Make the Array Increasing (in C)
• Problem 2079. Watering Plants
• Problem 2131. Longest Palindrome by Concatenating Two Letter Words
• Problem 2215. Find the Difference of Two Arrays (in C)
• Problem 2221. Find Triangular Sum of an Array
• Problem 2317. Maximum XOR After Operations
• Problem 2359. Find Closest Node to Given Two Nodes
• Problem 2442. Count Number of Distinct Integers After Reverse Operations
• Problem 2500. Delete Greatest Value in Each Row
• Problem 2553. Separate the Digits in an Array
• Problem 2656. Maximum Sum With Exactly K Elements
• Problem 2697. Lexicographically Smallest Palindrome
• Problem 2901. Longest Unequal Adjacent Groups Subsequence II (in C)
• Problem 2913. Subarrays Distinct Element Sum of Squares I
• Problem 2918. Minimum Equal Sum of Two Arrays After Replacing Zeros (in C)
• Problem 3019. Number of Changing Keys
• Problem 3158. Find the XOR of Numbers Which Appear Twice
• Problem 3324. Find the Sequence of Strings Appeared on the Screen
• Problem 3340. Check Balanced String (in C)
• Problem 3355. Zero Array Transformation I
• Problem 3362. Zero Array Transformation III
• Problem 3541. Find Most Frequent Vowel and Consonant
• Problem 3550. Smallest Index With Digit Sum Equal to Index

Other Changes

• Removed setup Ninja action in CI workflows
• Updated development dependencies

Full Changelog: 202506...202507

June 2025

What's Changed

Problem Solved

• Solve Problem 561. Array Partition
• Solve Problem 700. Search in a Binary Search Tree
• Solve Problem 797. All Paths From Source to Target (in C)
• Solve Problem 980. Unique Paths III (in C)
• Solve Problem 1290. Convert Binary Number in a Linked List to Integer
• Solve Problem 1323. Maximum 69 Number
• Solve Problem 1551. Minimum Operations to Make Array Equal
• Solve Problem 1557. Minimum Number of Vertices to Reach All Nodes
• Solve Problem 1768. Merge Strings Alternately
• Solve Problem 1817. Finding the Users Active Minutes
• Solve Problem 1827. Minimum Operations to Make the Array Increasing
• Solve Problem 1844. Replace All Digits with Characters
• Solve Problem 1967. Number of Strings That Appear as Substrings in Word
• Solve Problem 2094. Finding 3-Digit Even Numbers (in C)
• Solve Problem 2103. Rings and Rods
• Solve Problem 2119. A Number After a Double Reversal
• Solve Problem 2120. Execution of All Suffix Instructions Staying in a Grid
• Solve Problem 2215. Find the Difference of Two Arrays
• Solve Problem 2315. Count Asterisks
• Solve Problem 3340. Check Balanced String
• Solve Problem 2367. Number of Arithmetic Triplets (in C)
• Solve Problem 2616. Minimize the Maximum Difference of Pairs
• Solve Problem 2744. Find Maximum Number of String Pairs
• Solve Problem 2778. Sum of Squares of Special Elements
• Solve Problem 2900. Longest Unequal Adjacent Groups Subsequence I
• Solve Problem 2901. Longest Unequal Adjacent Groups Subsequence II
• Solve Problem 3024. Type of Triangle
• Solve Problem 3131. Find the Integer Added to Array I
• Solve Problem 3232. Find if Digit Game Can Be Won
• Solve Problem 3248. Snake in Matrix
• Solve Problem 3335. Total Characters in String After Transformations I
• Solve Problem 3337. Total Characters in String After Transformations II
• Solve Problem 3341. Find Minimum Time to Reach Last Room I (in C)
• Solve Problem 3342. Find Minimum Time to Reach Last Room II (in C)
• Solve Problem 3343. Count Number of Balanced Permutations
• Solve Problem 3502. Minimum Cost to Reach Every Position

Other Changes

• Reused Threeal's cache action
• Updated development dependencies
• Updated some problem implementations

Full Changelog: 202505...202506

May 2025

What's Changed

Problem Solved

• Problem 131. Palindrome Partitioning in C Language
• Problem 226. Invert Binary Tree
• Problem 535. Encode and Decode TinyURL
• Problem 654. Maximum Binary Tree
• Problem 709. To Lower Case
• Problem 771. Jewels and Stones (in C)
• Problem 790. Domino and Tromino Tiling
• Problem 797. All Paths From Source to Target
• Problem 804. Unique Morse Code Words
• Problem 807. Max Increase to Keep City Skyline
• Problem 832. Flipping an Image
• Problem 838. Push Dominoes
• Problem 980. Unique Paths III
• Problem 1007. Minimum Domino Rotations For Equal Row
• Problem 1008. Construct Binary Search Tree from Preorder Traversal
• Problem 1021. Remove Outermost Parentheses
• Problem 1128. Number of Equivalent Domino Pairs
• Problem 1221. Split a String in Balanced Strings
• Problem 1281. Subtract the Product and Sum of Digits of an Integer
• Problem 1282. Group the People Given the Group Size They Belong To
• Problem 1295. Find Numbers with Even Number of Digits
• Problem 1302. Deepest Leaves Sum
• Problem 1305. All Elements in Two Binary Search Trees
• Problem 1313. Decompress Run-Length Encoded List
• Problem 1315. Sum of Nodes with Even-Valued Grandparent
• Problem 1342. Number of Steps to Reduce a Number to Zero
• Problem 1353. Maximum Number of Events That Can Be Attended in C
• Problem 1365. How Many Numbers Are Smaller Than the Current Number
• Problem 1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree
• Problem 1389. Create Target Array in the Given Order
• Problem 1409. Queries on a Permutation With Key
• Problem 1431. Kids With the Greatest Number of Candies
• Problem 1470. Shuffle the Array in C
• Problem 1476. Subrectangle Queries
• Problem 1480. Running Sum of 1d Array
• Problem 1486. XOR Operation in an Array
• Problem 1528. Shuffle String
• Problem 1572. Matrix Diagonal Sum
• Problem 1588. Sum of All Odd Length Subarrays
• Problem 1603. Design Parking System
• Problem 1656. Design an Ordered Stream
• Problem 1672. Richest Customer Wealth
• Problem 1678. Goal Parser Interpretation
• Problem 1689. Partitioning Into Minimum Number Of Deci-Binary Numbers
• Problem 1720. Decode XORed Array
• Problem 1732. Find the Highest Altitude
• Problem 1773. Count Items Matching a Rule
• Problem 1816. Truncate Sentence
• Problem 1828. Queries on Number of Points Inside a Circle
• Problem 1832. Check if the Sentence Is Pangram
• Problem 1859. Sorting the Sentence
• Problem 1920. Build Array from Permutation
• Problem 2006. Count Number of Pairs With Absolute Difference K
• Problem 2071. Maximum Number of Tasks You Can Assign
• Problem 2094. Finding 3-Digit Even Numbers
• Problem 2114. Maximum Number of Words Found in Sentences
• Problem 2130. Maximum Twin Sum of a Linked List
• Problem 2160. Minimum Sum of Four Digit Number After Splitting Digits
• Problem 2194. Cells in a Range on an Excel Sheet
• Problem 2197. Replace Non-Coprime Numbers in Array (in C)
• Problem 2302. Count Subarrays With Score Less Than K
• Problem 2325. Decode the Message
• Problem 2236. Root Equals Sum of Children
• Problem 2367. Number of Arithmetic Triplets
• Problem 2396. Strictly Palindromic Number
• Problem 2520. Count the Digits That Divide a Number
• Problem 2574. Left and Right Sum Differences
• Problem 2652. Sum Multiples
• Problem 2751. Robot Collisions in C
• Problem 2798. Number of Employees Who Met the Target
• Problem 2824. Count Pairs Whose Sum is Less than Target
• Problem 2828. Check if a String Is an Acronym of Words
• Problem 2859. Sum of Values at Indices With K Set Bits
• Problem 2894. Divisible and Non-divisible Sums Difference
• Problem 2918. Minimum Equal Sum of Two Arrays After Replacing Zeros
• Problem 2942. Find Words Containing Character
• Problem 2956. Find Common Elements Between Two Arrays
• Problem 2974. Minimum Number Game
• Problem 3099. Harshad Number
• Problem 3146. Permutation Difference between Two Strings
• Problem 3162. Find the Number of Good Pairs I
• Problem 3194. Minimum Average of Smallest and Largest Elements
• Problem 3211. Generate Binary Strings Without Adjacent Zeros
• Problem 3271. Hash Divided String
• Problem 3280. Convert Date to Binary
• Problem 3285. Find Indices of Stable Mountains
• Problem 3289. The Two Sneaky Numbers of Digitville
• Problem 3300. Minimum Element After Replacement With Digit Sum
• Problem 3341. Find Minimum Time to Reach Last Room I
• Problem 3342. Find Minimum Time to Reach Last Room II
• Problem 3392. Count Subarrays of Length Three With a Condition
• Problem 3427. Sum of Variable Length Subarrays
• Problem 3467. Transform Array by Parity (in C)
• Problem 3498. Reverse Degree of a String
• Problem 3512. Minimum Operations to Make Array Sum Divisible by K

Full Changelog: 202504...202505

April 2025

What's Changed

Problem Solved

• Solve Problem 8. String to Integer (atoi) (in C)
• Solve Problem 30. Substring with Concatenation of All Words
• Solve Problem 32. Longest Valid Parentheses
• Solve Problem 37. Sudoku Solver
• Solve Problem 38. Count and Say
• Solve Problem 42. Trapping Rain Water
• Solve Problem 43. Multiply Strings
• Solve Problem 47. Permutations II
• Solve Problem 54. Spiral Matrix
• Solve Problem 60. Permutation Sequence
• Solve Problem 71. Simplify Path
• Solve Problem 77. Combinations
• Solve Problem 82. Remove Duplicates from Sorted List II
• Solve Problem 84. Largest Rectangle in Histogram
• Solve Problem 86. Partition List
• Solve Problem 87. Scramble String
• Solve Problem 90. Subsets II
• Solve Problem 148. Sort List
• Solve Problem 190. Reverse Bits
• Solve Problem 217. Contains Duplicate
• Solve Problem 219. Contains Duplicate II
• Solve Problem 274. H-Index
• Solve Problem 283. Move Zeroes
• Solve Problem 284. Peeking Iterator
• Solve Problem 289. Game of Life
• Solve Problem 290. Word Pattern
• Solve Problem 295. Find Median from Data Stream
• Solve Problem 297. Serialize and Deserialize Binary Tree
• Solve Problem 313. Super Ugly Number
• Solve Problem 319. Bulb Switcher
• Solve Problem 334. Increasing Triplet Subsequence
• Solve Problem 338. Counting Bits
• Solve Problem 347. Top K Frequent Elements
• Solve Problem 357. Count Numbers with Unique Digits
• Solve Problem 367. Valid Perfect Square
• Solve Problem 368. Largest Divisible Subset (in C)
• Solve Problem 373. Find K Pairs with Smallest Sums
• Solve Problem 374. Guess Number Higher or Lower
• Solve Problem 383. Ransom Note
• Solve Problem 402. Remove K Digits
• Solve Problem 405. Convert a Number to Hexadecimal
• Solve Problem 407. Trapping Rain Water II
• Solve Problem 414. Third Maximum Number
• Solve Problem 416. Partition Equal Subset Sum
• Solve Problem 434. Number of Segments in a String
• Solve Problem 448. Find All Numbers Disappeared in an Array
• Solve Problem 451. Sort Characters By Frequency (without hash map)
• Solve Problem 459. Repeated Substring Pattern
• Solve Problem 504. Base 7
• Solve Problem 509. Fibonacci Number
• Solve Problem 520. Detect Capital
• Solve Problem 552. Student Attendance Record II
• Solve Problem 598. Range Addition II
• Solve Problem 605. Can Place Flowers
• Solve Problem 696. Count Binary Substrings
• Solve Problem 763. Partition Labels
• Solve Problem 771. Jewels and Stones
• Solve Problem 781. Rabbits in Forest
• Solve Problem 859. Buddy Strings
• Solve Problem 865. Smallest Subtree with all the Deepest Nodes
• Solve Problem 911. Online Election
• Solve Problem 914. X of a Kind in a Deck of Cards
• Solve Problem 1028. Recover a Tree From Preorder Traversal
• Solve Problem 1103. Distribute Candies to People
• Solve Problem 1108. Defanging an IP Address
• Solve Problem 1123. Lowest Common Ancestor of Deepest Leaves
• Solve Problem 1399. Count Largest Group
• Solve Problem 1470. Shuffle the Array
• Solve Problem 1513. Number of Substrings With Only 1s
• Solve Problem 1922. Count Good Numbers
• Solve Problem 1929. Concatenation of Array
• Solve Problem 2011. Final Value of Variable After Performing Operations
• Solve Problem 2033. Minimum Operations to Make a Uni-Value Grid (in C)
• Solve Problem 2140. Solving Questions With Brainpower
• Solve Problem 2145. Count the Hidden Sequences
• Solve Problem 2176. Count Equal and Divisible Pairs in an Array
• Solve Problem 2179. Count Good Triplets in an Array
• Solve Problem 2469. Convert the Temperature
• Solve Problem 2503. Maximum Number of Points From Grid Queries
• Solve Problem 2537. Count the Number of Good Subarrays
• Solve Problem 2551. Put Marbles in Bags
• Solve Problem 2563. Count the Number of Fair Pairs (without binary search)
• Solve Problem 2769. Find the Maximum Achievable Number
• Solve Problem 2780. Minimum Index of a Valid Split
• Solve Problem 2799. Count Complete Subarrays in an Array
• Solve Problem 2818. Apply Operations to Maximize Score
• Solve Problem 2843. Count Symmetric Integers
• Solve Problem 2845. Count of Interesting Subarrays
• Solve Problem 2873. Maximum Value of an Ordered Triplet I
• Solve Problem 2874. Maximum Value of an Ordered Triplet II
• Solve Problem 2999. Count the Number of Powerful Integers
• Solve Problem 3169. Count Days Without Meetings
• Solve Problem 3190. Find Minimum Operations to Make All Elements Divisible by Three
• Solve Problem 3254. Find the Power of K-Size Subarrays I
• Solve Problem 3272. Find the Count of Good Integers
• Solve Problem 3375. Minimum Operations to Make Array Values Equal to K
• Solve Problem 3396. Minimum Number of Operations to Make Elements in Array Distinct
• Solve Problem 3467. Transform Array by Parity
• Solve Problem 3516. Find Closest Person

Other Changes

• Integrated Lefthook
• Temporarily utilized GitHub's Cache Action
• Updated development dependencies

Full Changelog: 202503...202504