代码：

class Solution {
    int[][] dirs = {{-1,0},{1,0},{0,1},{0,-1}};
    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){
                    int[] start = {i,j};
                    int area = getArea(start,0,grid);
                    max = max>area?max:area;
                }
            }
        }
        return max;
    }
    public int getArea(int[] start, int area, int[][] grid){
        grid[start[0]][start[1]] = -1;
        area++;
        for(int i=0;i<dirs.length;i++){
            int x = start[0]+dirs[i][0];
            int y = start[1]+dirs[i][1];
            if(x>=0&&x<grid.length&&y>=0&&y<grid[0].length&&grid[x][y]==1){
                int[] cur = {x,y};
                area = getArea(cur,area,grid);
            }
        }
        return area;
    }
}