回溯法实现n皇后问题的c++output

以下是回溯法实现n皇后问题的C++代码示例：

#include <iostream>
#include <vector>

using namespace std;

void solveNQueens(int n, vector<vector<string>>& res, vector<string>& board, vector<bool>& col, vector<bool>& dia1, vector<bool>& dia2, int row) {
    if (row == n) {
        res.push_back(board);
        return;
    }
    for (int i = 0; i < n; i++) {
        if (!col[i] && !dia1[row + i] && !dia2[row - i + n - 1]) {
            board[row][i] = 'Q';
            col[i] = true;
            dia1[row + i] = true;
            dia2[row - i + n - 1] = true;
            solveNQueens(n, res, board, col, dia1, dia2, row + 1);
            board[row][i] = '.';
            col[i] = false;
            dia1[row + i] = false;
            dia2[row - i + n - 1] = false;
        }
    }
}

vector<vector<string>> solveNQueens(int n) {
    vector<vector<string>> res;
    vector<string> board(n, string(n, '.'));
    vector<bool> col(n, false);
    vector<bool> dia1(2 * n - 1, false);
    vector<bool> dia2(2 * n - 1, false);
    solveNQueens(n, res, board, col, dia1, dia2, 0);
    return res;
}

int main() {
    int n = 4;
    vector<vector<string>> res = solveNQueens(n);
    for (auto& board : res) {
        for (auto& row : board) {
            cout << row << endl;
        }
        cout << endl;
    }
    return 0;
}

输出结果：

.Q..
...Q
Q...
..Q.

..Q.
Q...
...Q
.Q..