题解 | 机器人的运动范围

#include <vector>
class Solution {
public:
    int dir[4][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
    int res = 0;

    int cal(int n)
    {
        int sum = 0;
        while(n)
        {
            sum += n % 10;
            n /= 10;
        }
        return sum;
    }

    void dfs(int i, int j, int rows, int cols, int threshold, vector<vector<bool>>& vis)
    {
        if(vis[i][j] || i < 0 || j < 0 || i >= rows || j >= cols) return;
        if(cal(i) + cal(j) > threshold) return;
        res ++;
        vis[i][j] = true;
        for(int k = 0; k < 4; k ++)
        {
            dfs(i + dir[k][0], j + dir[k][1], rows, cols, threshold, vis);
        }
    }

    int movingCount(int threshold, int rows, int cols) {
        if(threshold <= 0) return 1;
        vector<vector<bool> > vis(rows, vector<bool>(cols, false));
        dfs(0, 0, rows, cols, threshold, vis);
        return res;
    }

};