【DFS】LeetCode 52. N-Queens II

LeetCode 52. N-Queens II

Solution1:我的答案
教科书一样的回溯法
《程序员面试金典》中有一道一毛一样的题啊!

class Solution {
public:
    int totalNQueens(int n) {
        vector<int> temp;
        int num = 0;
        my_count(temp, num, n);
        return num;
    }

    void my_count(vector<int> temp, int &num, int n) { //temp临时答案,num总次数,n棋盘大小
        if (temp.size() == n) {
            num++;
            return;
        } else {
            for (int i = 0; i < n; i++) {
                temp.push_back(i);
                if (isValid(temp)) 
                    my_count(temp, num, n);
                temp.pop_back();
            }
        }
    }

    bool isValid(vector<int>& temp) {
        if (temp.size() == 1) return true;
        else {
            int k = temp.size();
            for (int i = 0; i < temp.size() - 1; i++) {
                if(temp[i] == temp[k - 1] || abs(i - k + 1) == abs(temp[i] - temp[k - 1]))
                    return false;
            }
            return true;
        }
    }
};

你可能感兴趣的:(LeetCode练习题,LeetCode,52.,N-Queens,II)