题解 | #N皇后问题#

class Solution {
public:
    /**
     * 
     * @param n int整型 the n
     * @return int整型
     */
    void function(int n, int num, int& res, vector<bool>& pathRow, vector<bool>& pathCol, vector<bool>& pathX, vector<bool>& pathY) {
        if(num == n) {
            res++;
            return;
        }
//         num 代表行数，i代表列数，n-num+i和num+i代表两个斜向
        for(int i = 0; i < n; i++) {
            if(!pathRow[num] && !pathCol[i] && !pathX[n-num+i] && !pathY[num + i]) {
                pathRow[num] = true;
                pathCol[i] = true;
                pathX[n-num+i]=true;
                pathY[num + i] = true;
                function(n, num + 1, res, pathRow, pathCol, pathX, pathY);
                pathRow[num] = false;
                pathCol[i] = false;
                pathX[n-num+i] = false;
                pathY[num + i] = false;
            }
        }
    }
    int Nqueen(int n) {
        // write code here
        vector<bool> pathRow(10);
        vector<bool> pathCol(10);
        vector<bool> pathX(20);
        vector<bool> pathY(20);
        int res = 0;
        function(n, 0, res, pathRow, pathCol, pathX, pathY);
        return res;
    }
};