劍指offer——機器人的活動範圍

class Solution {
public:
    int movingCount(int threshold, int rows, int cols)
    {
        if(threshold<0||rows<1||cols<1)
            return 0;
        int countnum=0;
        bool *visited=new bool[rows*cols];//用于标記已通路過的格子
        fill(visited,visited+cols*rows,false);
        travel(threshold,0,0,rows,cols,countnum,visited);
        delete[] visited;
        return countnum;
    }
    
    void travel(int threshold,int row,int col,int rows,int cols,int &countnum,bool* visited){
        if(count(row)+count(col)>threshold)
            return ;
        if(row>=0&&row<rows&&col>=0&&col<cols&&!visited[row*cols+col]){
            visited[row*cols+col]=true;
            countnum+=1;
            travel(threshold,row+1,col,rows,cols,countnum,visited);
            travel(threshold,row-1,col,rows,cols,countnum,visited);
            travel(threshold,row,col+1,rows,cols,countnum,visited);
            travel(threshold,row,col-1,rows,cols,countnum,visited);
        }
    }
    
    int count(int num){
        int sum=0;
        while(num>0){
            sum+=num%10;
            num/=10;
        }
        return sum;
    }
};