```
class Solution {
public int maxAreaOfIsland(int[][] grid) {
int max = 0;
for (int i = 0; i < grid.length; i++) {
for (int j = 0; j < grid[0].length; j++) {
if (grid[i][j] == 1) {
max = Math.max(max, helper(grid, i, j));
}
}
}
return max;
}
public int helper(int[][] grid, int i, int j) {
if (i < 0 || i >= grid.length || j < 0 || j >= grid[0].length || grid[i][j] == 0) {
return 0;
}
grid[i][j] = 0;
return 1 + helper(grid, i - 1, j) + helper(grid, i + 1, j) + helper(grid, i, j - 1) + helper(grid, i, j + 1);
}
}
```