Depth-First Search/Max Area of IslandMedium

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Max Area of Island

Depth-First Search·Medium

You are given an m x n binary matrix grid. An island is a group of 1s (land) connected 4-directionally (horizontal or vertical). The area of an island is the number of cells with value 1 in the island.

Return the maximum area of an island in the grid. If there is no island, return 0.

Examples

Input: grid = [[0,0,1,0,0,0,0,1,0,0,0,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,1,1,0,1,0,0,0,0,0,0,0,0],[0,1,0,0,1,1,0,0,1,0,1,0,0],[0,1,0,0,1,1,0,0,1,1,1,0,0],[0,0,0,0,0,0,0,0,0,0,1,0,0],[0,0,0,0,0,0,0,1,1,1,0,0,0],[0,0,0,0,0,0,0,1,1,0,0,0,0]]

Output: 6

Input: grid = [[0,0,0,0,0,0,0,0]]

Output: 0

Constraints

m == grid.length
n == grid[i].length
1 <= m, n <= 50
grid[i][j] is 0 or 1.

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Tests

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Passed32 ms

First attempt — retry to track metric movement here.

Your approach

Pattern:Depth-First Search
Time:O(N)
Space:O(1)

Complete approach — pattern and complexity both named.

Coach

What you got right

You correctly matched the sorted input requirement and implemented a linear-time scan using two pointers.

Where it diverged

No divergence detected. The code correctly aligns with the stated approach.

Next attempt: focus on

Try solving related sliding window problems to build familiarity with two-pointer variants.

Signals

No signals fired — clean run, you stayed in flow.