change the value of the given grid in place,

```
def maxAreaOfIsland(self, grid):
m, n = len(grid), len(grid[0])
def dfs(i, j):
if 0 <= i < m and 0 <= j < n and grid[i][j]:
grid[i][j] = 0
return 1 + dfs(i - 1, j) + dfs(i, j + 1) + dfs(i + 1, j) + dfs(i, j - 1)
return 0
result = 0
for x in range(m):
for y in range(n):
if grid[x][y]:
result = max(result, dfs(x, y))
return result
```