matrix

Valid Sudoku

Check if a 9x9 Sudoku board is valid by scanning rows, columns, and sub-boxes with hash lookups, ensuring no duplicates …

Sudoku Solver

Solve the Sudoku puzzle by filling empty cells while respecting Sudoku's rules using array scanning and backtracking.

Rotate Image

Rotate an n x n matrix 90 degrees clockwise in-place using array manipulation and mathematical indexing techniques effic…

Spiral Matrix

Given an m x n matrix, return all elements in spiral order starting from the top-left corner.

Spiral Matrix II

Generate a spiral matrix of size n x n, filled with elements from 1 to n² in spiral order, for interview-focused solving…

Unique Paths II

Calculate the number of unique paths from top-left to bottom-right in a grid with obstacles using dynamic programming st…

Minimum Path Sum

Compute the minimum sum from top-left to bottom-right in a grid using state transition dynamic programming efficiently.

Set Matrix Zeroes

Modify the matrix in place by setting rows and columns to zero when an element is zero.

Search a 2D Matrix

Search a 2D matrix efficiently using binary search over its linearized index, ensuring correctness in row-major sorted a…

Word Search

Solve Word Search with backtracking by exploring adjacent cells to match a target word in a grid.

Maximal Rectangle

Compute the largest rectangle of 1's in a binary matrix using dynamic programming and stack-based state transitions effi…

Surrounded Regions

Transform the matrix in-place by marking regions surrounded by 'X' as 'X', while keeping border-adjacent 'O's intact.

Dungeon Game

Calculate the minimum initial health the knight needs to survive the dungeon using state transition dynamic programming …

Number of Islands

Count the number of distinct islands in a binary grid using array traversal combined with depth-first search exploration…

Word Search II

Solve the Word Search II problem using backtracking with pruning to find all words on a board of characters.

Maximal Square

Maximal Square is a matrix-based dynamic programming problem that focuses on finding the largest square filled with 1's.

Search a 2D Matrix II

Efficiently search for a target in a 2D matrix using binary search and matrix properties.

Game of Life

Solve the Game of Life by updating each cell based on its eight neighbors using Array and Matrix simulation patterns eff…

Range Sum Query 2D - Immutable

Design a 2D matrix class that efficiently handles sum queries with O(1) time complexity using a prefix sum approach.

Longest Increasing Path in a Matrix

Find the length of the longest increasing path in a matrix with given movement constraints using graph techniques.

Max Sum of Rectangle No Larger Than K

Solve the "Max Sum of Rectangle No Larger Than K" problem using binary search over the valid sum space to optimize space…

Kth Smallest Element in a Sorted Matrix

Find the kth smallest element in a sorted n x n matrix using efficient binary search or heap strategies for optimized me…

Trapping Rain Water II

Solve Trapping Rain Water II using breadth-first search and priority queues for efficient water trapping in a matrix.

Pacific Atlantic Water Flow

Find all cells on an island where water can flow to both the Pacific and Atlantic oceans using DFS or BFS.