Matrix LeetCode Problems: All 216,
With Python Solutions

Every problem in this library that LeetCode tags Matrix. 178 of them carry a complete Python solution, a worked example and the time and space complexity of the approach.

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Easy: 32
Medium: 125
Hard: 59

1 pattern

How Matrix problems are solved

A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Matrix problems — each one explains the approach, gives a Python template and states its complexity.

Matrix and GridTreat a 2-D grid as a graph whose neighbours are the four adjacent cells.

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python

Please analyze this context and help me answer the question or solve the problem.

Technical interview · 45 minsolution.pyShared editor · Python 3Longest substring without repeatsMediumGiven a string s, return the length of the longest contiguous substring in which every character is unique.s = "abcabcbb"
→ 31def length_of_longest_substring(s: str) -> int:2 last_seen = {}3 left = best = 04 for right, ch in enumerate(s):5 if ch in last_seen and last_seen[ch] >= left:

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

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python

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python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

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QuitEscHide+QCapture+PCrop+OSubmit+EnterPress to get answerLeft/Right+Up/Down+

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python

Please analyze this context and help me answer the question or solve the problem.

python

def length_of_longest_substring(s: str) -> int:    last_seen = {}                    # char -> index    left = best = 0    for right, ch in enumerate(s):        if ch in last_seen and last_seen[ch] >= left:            left = last_seen[ch] + 1  # jump past it        last_seen[ch] = right        best = max(best, right - left + 1)    return best    last_seen = {}                    # char -> index

Approach

At each index r, the window's left edge is:

left r = max (left r -1, last[s r] + 1)

Time O(n): each character enters and leaves the window once.
Space O(min(n, k)): k is the size of the character set.

Type your message...

GPT-6.1 TerraClear chat

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Matrix problems by difficulty

Showing the first 200 of 216 problems. Problems with a complete Python solution are listed first, then by ascending problem number.

Easy (32)

Easy problems
No.	Problem	Topics
0463	Island Perimeter	Depth-First Search, Breadth-First Search, Array +1
0566	Reshape the Matrix	Array, Matrix, Simulation
0661	Image Smoother	Array, Matrix
0733	Flood Fill	Depth-First Search, Breadth-First Search, Array +1
0766	Toeplitz Matrix	Array, Matrix
0832	Flipping an Image	Bit Manipulation, Array, Two Pointers +2
0867	Transpose Matrix	Array, Matrix, Simulation
0883	Projection Area of 3D Shapes	Geometry, Array, Math +1
0892	Surface Area of 3D Shapes	Geometry, Array, Math +1
0999	Available Captures for Rook	Array, Matrix, Simulation
1030	Matrix Cells in Distance Order	Geometry, Array, Math +2
1260	Shift 2D Grid	Array, Matrix, Simulation
1275	Find Winner on a Tic Tac Toe Game	Array, Hash Table, Matrix +1
1337	The K Weakest Rows in a Matrix	Array, Binary Search, Matrix +2
1351	Count Negative Numbers in a Sorted Matrix	Array, Binary Search, Matrix
1380	Lucky Numbers in a Matrix	Array, Matrix
1572	Matrix Diagonal Sum	Array, Matrix
1582	Special Positions in a Binary Matrix	Array, Matrix
1672	Richest Customer Wealth	Array, Matrix
1886	Determine Whether Matrix Can Be Obtained By Rotation	Array, Matrix
2022	Convert 1D Array Into 2D Array	Array, Matrix, Simulation
2133	Check if Every Row and Column Contains All Numbers	Array, Hash Table, Matrix
2319	Check if Matrix Is X-Matrix	Array, Matrix
2373	Largest Local Values in a Matrix	Array, Matrix
2500	Delete Greatest Value in Each Row	Array, Matrix, Sorting +2
2614	Prime In Diagonal	Array, Math, Matrix +1
2639	Find the Width of Columns of a Grid	Array, Matrix
2643	Row With Maximum Ones	Array, Matrix
2923	Find Champion I	Array, Matrix
2946	Matrix Similarity After Cyclic Shifts	Array, Math, Matrix +1
2965	Find Missing and Repeated Values	Array, Hash Table, Math +1
0422	Valid Word SquarePremium	Array, Matrix

Medium (113)

Medium problems
No.	Problem	Topics
0036	Valid Sudoku	Array, Hash Table, Matrix
0048	Rotate Image	Array, Math, Matrix
0054	Spiral Matrix	Array, Matrix, Simulation
0059	Spiral Matrix II	Array, Matrix, Simulation
0063	Unique Paths II	Array, Dynamic Programming, Matrix
0064	Minimum Path Sum	Array, Dynamic Programming, Matrix
0073	Set Matrix Zeroes	Array, Hash Table, Matrix
0074	Search a 2D Matrix	Array, Binary Search, Matrix
0079	Word Search	Depth-First Search, Array, String +2
0130	Surrounded Regions	Depth-First Search, Breadth-First Search, Union Find +2
0200	Number of Islands	Depth-First Search, Breadth-First Search, Union Find +2
0221	Maximal Square	Array, Dynamic Programming, Matrix
0240	Search a 2D Matrix II	Array, Binary Search, Divide and Conquer +1
0289	Game of Life	Array, Matrix, Simulation
0304	Range Sum Query 2D - Immutable	Design, Array, Matrix +1
0378	Kth Smallest Element in a Sorted Matrix	Array, Binary Search, Matrix +2
0417	Pacific Atlantic Water Flow	Depth-First Search, Breadth-First Search, Array +1
0419	Battleships in a Board	Depth-First Search, Array, Matrix
0427	Construct Quad Tree	Tree, Array, Divide and Conquer +1
0498	Diagonal Traverse	Array, Matrix, Simulation
0529	Minesweeper	Depth-First Search, Breadth-First Search, Array +1
0542	01 Matrix	Breadth-First Search, Array, Dynamic Programming +1
0695	Max Area of Island	Depth-First Search, Breadth-First Search, Union Find +2
0794	Valid Tic-Tac-Toe State	Array, Matrix
0807	Max Increase to Keep City Skyline	Greedy, Array, Matrix
0835	Image Overlap	Array, Matrix
0840	Magic Squares In Grid	Array, Hash Table, Math +1
0861	Score After Flipping Matrix	Greedy, Bit Manipulation, Array +1
0885	Spiral Matrix III	Array, Matrix, Simulation
0909	Snakes and Ladders	Breadth-First Search, Array, Matrix
0931	Minimum Falling Path Sum	Array, Dynamic Programming, Matrix
0934	Shortest Bridge	Depth-First Search, Breadth-First Search, Array +1
0959	Regions Cut By Slashes	Depth-First Search, Breadth-First Search, Union Find +3
0994	Rotting Oranges	Breadth-First Search, Array, Matrix
1020	Number of Enclaves	Depth-First Search, Breadth-First Search, Union Find +2
1034	Coloring A Border	Depth-First Search, Breadth-First Search, Array +1
1072	Flip Columns For Maximum Number of Equal Rows	Array, Hash Table, Matrix
1091	Shortest Path in Binary Matrix	Breadth-First Search, Array, Matrix
1139	Largest 1-Bordered Square	Array, Dynamic Programming, Matrix
1162	As Far from Land as Possible	Breadth-First Search, Array, Dynamic Programming +1
1219	Path with Maximum Gold	Array, Backtracking, Matrix
1222	Queens That Can Attack the King	Array, Matrix, Simulation
1253	Reconstruct a 2-Row Binary Matrix	Greedy, Array, Matrix
1254	Number of Closed Islands	Depth-First Search, Breadth-First Search, Union Find +2
1267	Count Servers that Communicate	Depth-First Search, Breadth-First Search, Union Find +3
1277	Count Square Submatrices with All Ones	Array, Dynamic Programming, Matrix
1292	Maximum Side Length of a Square with Sum Less than or Equal to Threshold	Array, Binary Search, Matrix +1
1314	Matrix Block Sum	Array, Matrix, Prefix Sum
1329	Sort the Matrix Diagonally	Array, Matrix, Sorting
1391	Check if There is a Valid Path in a Grid	Depth-First Search, Breadth-First Search, Union Find +2
1476	Subrectangle Queries	Design, Array, Matrix
1504	Count Submatrices With All Ones	Stack, Array, Dynamic Programming +2
1536	Minimum Swaps to Arrange a Binary Grid	Greedy, Array, Matrix
1559	Detect Cycles in 2D Grid	Depth-First Search, Breadth-First Search, Union Find +2
1594	Maximum Non Negative Product in a Matrix	Array, Dynamic Programming, Matrix
1605	Find Valid Matrix Given Row and Column Sums	Greedy, Array, Matrix
1631	Path With Minimum Effort	Depth-First Search, Breadth-First Search, Union Find +4
1706	Where Will the Ball Fall	Array, Matrix, Simulation
1727	Largest Submatrix With Rearrangements	Greedy, Array, Matrix +1
1738	Find Kth Largest XOR Coordinate Value	Bit Manipulation, Array, Divide and Conquer +5
1765	Map of Highest Peak	Breadth-First Search, Array, Matrix
1861	Rotating the Box	Array, Two Pointers, Matrix
1878	Get Biggest Three Rhombus Sums in a Grid	Array, Math, Matrix +3
1895	Largest Magic Square	Array, Matrix, Prefix Sum
1901	Find a Peak Element II	Array, Binary Search, Matrix
1905	Count Sub Islands	Depth-First Search, Breadth-First Search, Union Find +2
1914	Cyclically Rotating a Grid	Array, Matrix, Simulation
1926	Nearest Exit from Entrance in Maze	Breadth-First Search, Array, Matrix
1937	Maximum Number of Points with Cost	Array, Dynamic Programming, Matrix
1958	Check if Move is Legal	Array, Enumeration, Matrix
1975	Maximum Matrix Sum	Greedy, Array, Matrix
1981	Minimize the Difference Between Target and Chosen Elements	Array, Dynamic Programming, Matrix
1992	Find All Groups of Farmland	Depth-First Search, Breadth-First Search, Array +1
2017	Grid Game	Array, Matrix, Prefix Sum
2018	Check if Word Can Be Placed In Crossword	Array, Enumeration, Matrix
2033	Minimum Operations to Make a Uni-Value Grid	Array, Math, Matrix +1
2125	Number of Laser Beams in a Bank	Array, Math, String +1
2146	K Highest Ranked Items Within a Price Range	Breadth-First Search, Array, Matrix +2
2245	Maximum Trailing Zeros in a Cornered Path	Array, Matrix, Prefix Sum
2257	Count Unguarded Cells in the Grid	Array, Matrix, Simulation
2304	Minimum Path Cost in a Grid	Array, Dynamic Programming, Matrix
2326	Spiral Matrix IV	Array, Linked List, Matrix +1
2352	Equal Row and Column Pairs	Array, Hash Table, Matrix +1
2397	Maximum Rows Covered by Columns	Bit Manipulation, Array, Backtracking +2
2428	Maximum Sum of an Hourglass	Array, Matrix, Prefix Sum
2482	Difference Between Ones and Zeros in Row and Column	Array, Matrix, Simulation
2536	Increment Submatrices by One	Array, Matrix, Prefix Sum
2545	Sort the Students by Their Kth Score	Array, Matrix, Sorting
2556	Disconnect Path in a Binary Matrix by at Most One Flip	Depth-First Search, Breadth-First Search, Array +2
2596	Check Knight Tour Configuration	Depth-First Search, Breadth-First Search, Array +2
2658	Maximum Number of Fish in a Grid	Depth-First Search, Breadth-First Search, Union Find +2
2661	First Completely Painted Row or Column	Array, Hash Table, Matrix
2679	Sum in a Matrix	Array, Matrix, Sorting +2
2684	Maximum Number of Moves in a Grid	Array, Dynamic Programming, Matrix
2711	Difference of Number of Distinct Values on Diagonals	Array, Hash Table, Matrix
2812	Find the Safest Path in a Grid	Breadth-First Search, Union Find, Array +3
2850	Minimum Moves to Spread Stones Over Grid	Breadth-First Search, Array, Dynamic Programming +1
2906	Construct Product Matrix	Array, Matrix, Prefix Sum
0286	Walls and GatesPremium	Breadth-First Search, Array, Matrix
0308	Range Sum Query 2D - MutablePremium	Design, Binary Indexed Tree, Segment Tree +2
0311	Sparse Matrix MultiplicationPremium	Array, Hash Table, Matrix
0348	Design Tic-Tac-ToePremium	Design, Array, Hash Table +2
0361	Bomb EnemyPremium	Array, Dynamic Programming, Matrix
0490	The MazePremium	Depth-First Search, Breadth-First Search, Array +1
0505	The Maze IIPremium	Depth-First Search, Breadth-First Search, Graph +4
0531	Lonely Pixel IPremium	Array, Hash Table, Matrix
0533	Lonely Pixel IIPremium	Array, Hash Table, Matrix
0562	Longest Line of Consecutive One in MatrixPremium	Array, Dynamic Programming, Matrix
0723	Candy CrushPremium	Array, Two Pointers, Matrix +1
0750	Number Of Corner RectanglesPremium	Array, Math, Dynamic Programming +1
1102	Path With Maximum Minimum ValuePremium	Depth-First Search, Breadth-First Search, Union Find +4
1198	Find Smallest Common Element in All RowsPremium	Array, Hash Table, Binary Search +2
1428	Leftmost Column with at Least a OnePremium	Array, Binary Search, Interactive +1

Hard (55)

Hard problems
No.	Problem	Topics
0037	Sudoku Solver	Array, Hash Table, Backtracking +1
0085	Maximal Rectangle	Stack, Array, Dynamic Programming +2
0174	Dungeon Game	Array, Dynamic Programming, Matrix
0212	Word Search II	Trie, Array, String +2
0329	Longest Increasing Path in a Matrix	Depth-First Search, Breadth-First Search, Graph +5
0363	Max Sum of Rectangle No Larger Than K	Array, Binary Search, Matrix +2
0407	Trapping Rain Water II	Breadth-First Search, Array, Matrix +1
0675	Cut Off Trees for Golf Event	Breadth-First Search, Array, Matrix +1
0741	Cherry Pickup	Array, Dynamic Programming, Matrix
0749	Contain Virus	Depth-First Search, Breadth-First Search, Array +2
0773	Sliding Puzzle	Breadth-First Search, Memoization, Array +3
0778	Swim in Rising Water	Depth-First Search, Breadth-First Search, Union Find +4
0782	Transform to Chessboard	Bit Manipulation, Array, Math +1
0803	Bricks Falling When Hit	Union Find, Array, Matrix
0827	Making A Large Island	Depth-First Search, Breadth-First Search, Union Find +2
0864	Shortest Path to Get All Keys	Bit Manipulation, Breadth-First Search, Array +1
0980	Unique Paths III	Bit Manipulation, Array, Backtracking +1
1074	Number of Submatrices That Sum to Target	Array, Hash Table, Matrix +1
1210	Minimum Moves to Reach Target with Rotations	Breadth-First Search, Array, Matrix
1263	Minimum Moves to Move a Box to Their Target Location	Breadth-First Search, Array, Matrix +1
1284	Minimum Number of Flips to Convert Binary Matrix to Zero Matrix	Bit Manipulation, Breadth-First Search, Array +2
1289	Minimum Falling Path Sum II	Array, Dynamic Programming, Matrix
1293	Shortest Path in a Grid with Obstacles Elimination	Breadth-First Search, Array, Matrix
1301	Number of Paths with Max Score	Array, Dynamic Programming, Matrix
1349	Maximum Students Taking Exam	Bit Manipulation, Array, Dynamic Programming +2
1368	Minimum Cost to Make at Least One Valid Path in a Grid	Breadth-First Search, Graph, Array +3
1439	Find the Kth Smallest Sum of a Matrix With Sorted Rows	Array, Binary Search, Matrix +1
1444	Number of Ways of Cutting a Pizza	Memoization, Array, Dynamic Programming +2
1463	Cherry Pickup II	Array, Dynamic Programming, Matrix
1568	Minimum Number of Days to Disconnect Island	Depth-First Search, Breadth-First Search, Array +2
1595	Minimum Cost to Connect Two Groups of Points	Bit Manipulation, Array, Dynamic Programming +2
1632	Rank Transform of a Matrix	Union Find, Graph, Topological Sort +3
1728	Cat and Mouse II	Graph, Topological Sort, Memoization +5
1970	Last Day Where You Can Still Cross	Depth-First Search, Breadth-First Search, Union Find +3
2088	Count Fertile Pyramids in a Land	Array, Dynamic Programming, Matrix
2132	Stamping the Grid	Greedy, Array, Matrix +1
2258	Escape the Spreading Fire	Breadth-First Search, Array, Binary Search +1
2267	Check if There Is a Valid Parentheses String Path	Array, Dynamic Programming, Matrix
2290	Minimum Obstacle Removal to Reach Corner	Breadth-First Search, Graph, Array +3
2328	Number of Increasing Paths in a Grid	Depth-First Search, Breadth-First Search, Graph +5
2392	Build a Matrix With Conditions	Graph, Topological Sort, Array +1
2435	Paths in Matrix Whose Sum Is Divisible by K	Array, Dynamic Programming, Matrix
2503	Maximum Number of Points From Grid Queries	Breadth-First Search, Union Find, Array +4
2573	Find the String with LCP	Greedy, Union Find, Array +3
2577	Minimum Time to Visit a Cell In a Grid	Breadth-First Search, Graph, Array +3
2617	Minimum Number of Visited Cells in a Grid	Stack, Breadth-First Search, Union Find +5
2713	Maximum Strictly Increasing Cells in a Matrix	Memoization, Array, Hash Table +5
2732	Find a Good Subset of the Matrix	Bit Manipulation, Array, Hash Table +1
2931	Maximum Spending After Buying Items	Greedy, Array, Matrix +2
0296	Best Meeting PointPremium	Array, Math, Matrix +1
0302	Smallest Rectangle Enclosing Black PixelsPremium	Depth-First Search, Breadth-First Search, Array +2
0317	Shortest Distance from All BuildingsPremium	Breadth-First Search, Array, Matrix
0499	The Maze IIIPremium	Depth-First Search, Breadth-First Search, Graph +5
0568	Maximum Vacation DaysPremium	Array, Dynamic Programming, Matrix
0631	Design Excel Sum FormulaPremium	Graph, Design, Topological Sort +4

How Matrix problems are solved

When the Matrix problem arrives live.

Approach

Approach

Approach

Matrix problems by difficulty

Easy (32)32

Medium (113)113

Hard (55)55

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Easy (32)

Medium (113)

Hard (55)