岛屿的最大面积

[[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]]

public int maxAreaOfIsland(int[][] grid){
        if(grid==null || grid.length==0){
            return 0;
        }
        int maxArea = 0;
        for(int i=0;i<grid.length;i++){
            for(int j=0;j<grid[0].length;j++){
                maxArea = Math.max(maxArea, dfs(grid,i,j));
            }
        }
        return maxArea;
    }
    
    private int dfs(int[][] grid,int x,int y){
        if(x<0||x>=grid.length||y<0||y>=grid[0].length||grid[x][y]==0){
            return 0;
        }
        grid[x][y] = 0;
        int area = 1;
        int[][] direction = {{0,1},{0,-1},{1,0},{-1,0}};
        for(int[] d:direction){
            area += dfs(grid, x+d[0], y+d[1]);
        }
        return area;
    }