695. Max Area of Island

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

        return 1 + dfsHelper(grid, i + 1, j) + dfsHelper(grid, i - 1, j) + 
            dfsHelper(grid, i, j + 1) +dfsHelper(grid, i, j - 1);
        
    }
}