Java 代码

class Solution {
    int count=0;
    public int movingCount(int threshold, int rows, int cols)
    {
        if(rows==0||cols==0)return 0;
        boolean [][] vt=new boolean[rows][cols];

        dfs(threshold,rows,cols,0,0,vt);
        return count;
    }

    void  dfs(int threshold,int rows,int cols,int x,int y,boolean [][]vt){

        if(sum(x)+sum(y)>threshold)return;
        int [] dx={-1,0,1,0};
        int [] dy={0,1,0,-1};

        vt[x][y]=true;
        count++;
        for(int i=0;i<4;i++){
            int nx=x+dx[i];
            int ny=y+dy[i];
            if(nx>=0&&nx<rows&&ny>=0&&ny<cols&&vt[nx][ny]==false){
                dfs(threshold,rows,cols,nx,ny,vt);

            }
        }

    }

    int sum(int a){
        int b=0;
        while(a>0){
            b+=a%10;
            a/=10;
        }
        return b;
    }
}