【攻克力扣200题--35】200. 岛屿数量

DFS

var numIslands = function(grid) {
    let m=grid.length;
    if(m==0) return 0;
    let n=grid[0].length;
    let direction=[[-1,0],[0,-1],[1,0],[0,1]];
    let count=0;
    for(var i=0;i=m||j<0||j>=n||grid[i][j]==0) return ;
    grid[i][j]=0;
    for(var k=0;k<4;k++) dfs(grid,i+direction[k][0],j+direction[k][1]);
    }
    
    
    return count;
};