岛屿数量

问题

答案

var numIslands = function(grid) {
    const row=grid.length;
    const column=grid[0].length;
    function dfs(i,j){
        if(i<0||j<0||i>=row||j>=column||grid[i][j]!=='1') return;
        grid[i][j]='2';
        dfs(i,j-1);
        dfs(i,j+1);
        dfs(i-1,j);
        dfs(i+1,j);
    }
    let res=0;
    for(let i=0;i<row;i++){
        for(let j=0;j<column;j++){
            if(grid[i][j]==='1'){
                dfs(i,j);
                res++;
            }
        }
    }
    return res;
};

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