Max Area of Island LeetCode solution in Python

1
class Solution:
2
    def maxAreaOfIsland(self, grid: List[List[int]]) -> int:
3
        if not grid:
4
            return 0
5

6
        maxArea = 0
7

8
        for i in range(len(grid)):
9
            for j in range(len(grid[0])):
10
                if grid[i][j] == 1:  # run dfs only when we find a land
11
                    maxArea = max(maxArea, self.dfs(grid, i, j))
12

13
        return maxArea
14

15
    def dfs(self, grid, i, j):
16
        # conditions for out of bound and when we encounter water
17
        if i < 0 or j < 0 or i >= len(grid) or j >= len(grid[0]) or grid[i][j] != 1:
18
            return 0
19

20
        maxArea = 1
21
        grid[i][j] = "#"  # this will act as visited set
22
        maxArea += self.dfs(grid, i + 1, j)
23
        maxArea += self.dfs(grid, i - 1, j)
24
        maxArea += self.dfs(grid, i, j + 1)
25
        maxArea += self.dfs(grid, i, j - 1)
26

27
        return maxArea