Matrix
79 problems · 45 with full explanations
6 Easy25 Medium16 Hard
Matrix problems often involve BFS/DFS flood fill, dynamic programming on 2D grids, or spiral/diagonal traversal. For row × column DP, break it into 1D sub-problems column by column. Common pitfalls: boundary checks and modifying the input matrix in-place.
How to practice
To practice Matrix problems effectively, start with the Easy problems listed below, trace through each solution on paper, then re-implement without looking. When you can recognise the matrix pattern within 30 seconds of reading a new problem, move on to Medium difficulty. Use the related topic pages and our study guide for a structured progression.
Start here (Easy + explained)
All Matrix problems
- 36.Valid SudokuMedium
- 37.Sudoku SolverHard
- 73.Set Matrix ZeroesMedium
- 85.Maximal RectangleHard
- 174.Dungeon GameHard
- 212.Word Search IIHard
- 221.Maximal SquareMedium
- 304.Range Sum Query 2D - ImmutableMedium
- 329.Longest Increasing Path in a MatrixHard
- 407.Trapping Rain Water IIHard
- 417.Pacific Atlantic Water FlowMedium
- 498.Diagonal TraverseMedium
- 773.Sliding PuzzleHard
- 778.Swim in Rising WaterHard
- 790.Domino and Tromino TilingMedium
- 807.Max Increase to Keep City SkylineMedium
- 827.Making A Large IslandHard
- 840.Magic Squares In GridMedium
- 885.Spiral Matrix IIIMedium
- 909.Snakes and LaddersMedium
- 928.Minimize Malware Spread IIUnknown
- 959.Regions Cut By SlashesUnknown
- 1072.Flip Columns For Maximum Number of Equal RowsMedium
- 1267.Count Servers that CommunicateMedium
- 1277.Count Square Submatrices with All OnesMedium
- 1368.Minimum Cost to Make at Least One Valid Path in a GridHard
- 1380.Lucky Numbers in a MatrixEasy
- 1504.Count Submatrices With All OnesUnknown
- 1536.Minimum Swaps to Arrange a Binary GridUnknown
- 1568.Minimum Number of Days to Disconnect IslandUnknown
- 1582.Special Positions in a Binary MatrixUnknown
- 1605.Find Valid Matrix Given Row and Column SumsUnknown
- 1727.Largest Submatrix With RearrangementsUnknown
- 1765.Map of Highest PeakMedium
- 1861.Rotating the BoxEasy
- 1878.Get Biggest Three Rhombus Sums in a GridUnknown
- 1886.Determine Whether Matrix Can Be Obtained By RotationUnknown
- 1895.Largest Magic SquareUnknown
- 1905.Count Sub IslandsUnknown
- 1970.Last Day Where You Can Still CrossUnknown
- 1975.Maximum Matrix SumUnknown
- 2017.Grid GameUnknown
- 2022.Convert 1D Array Into 2D ArrayMedium
- 2033.Minimum Operations to Make a Uni-Value GridUnknown
- 2125.Number of Laser Beams in a BankMedium
- 2257.Count Unguarded Cells in the GridUnknown
- 2290.Minimum Obstacle Removal to Reach CornerHard
- 2326.Spiral Matrix IVHard
- 2392.Build a Matrix With ConditionsHard
- 2435.Paths in Matrix Whose Sum Is Divisible by KHard
- 2503.Maximum Number of Points From Grid QueriesHard
- 2536.Increment Submatrices by OneMedium
- 2573.Find the String with LCPUnknown
- 2577.Minimum Time to Visit a Cell In a GridHard
- 2639.Find the Width of Columns of a GridUnknown
- 2658.Maximum Number of Fish in a GridMedium
- 2661.First Completely Painted Row or ColumnMedium
- 2684.Maximum Number of Moves in a GridMedium
- 2718.Sum of Matrix After QueriesUnknown
- 2906.Construct Product MatrixEasy
- 2943.Maximize Area of Square Hole in GridMedium
- 2946.Matrix Similarity After Cyclic ShiftsEasy
- 2965.Find Missing and Repeated ValuesUnknown
- 2975.Maximum Square Area by Removing Fences From a FieldUnknown
- 3070.Count Submatrices with Top-Left Element and Sum Less Than kEasy
- 3122.Minimum Number of Operations to Satisfy ConditionsUnknown
- 3195.Find the Minimum Area to Cover All Ones IUnknown
- 3197.Find the Minimum Area to Cover All Ones IIUnknown
- 3212.Count Submatrices With Equal Frequency of X and YUnknown
- 3337.Total Characters in String After Transformations IIUnknown
- 3363.Find the Maximum Number of Fruits CollectedUnknown
- 3418.Maximum Amount of Money Robot Can EarnMedium
- 3446.Sort Matrix by DiagonalsMedium
- 3459.Length of Longest V-Shaped Diagonal SegmentEasy
- 3484.Design SpreadsheetMedium
- 3546.Equal Sum Grid Partition IUnknown
- 3548.Equal Sum Grid Partition IIUnknown
- 3567.Minimum Absolute Difference in Sliding SubmatrixUnknown
- 3643.Flip Square Submatrix VerticallyUnknown