算法.n皇后问题

#include<iostream>
using namespace std;
const int N = 10;
char a[N][N];
bool b[N], c[N], d[N];
int n;

void dfs(int u)
{
    if (u == n)
    {
        for (int i = 0; i < n; i++)puts(a[i]);
        puts("");
        return;
    }
    for (int i = 0; i < n; i++)
    {
        if (!b[i] && !c[u - i] && !d[i - u + n])
        {
            a[u][i] = 'Q';
            b[i] = c[u - i] = d[i - u + n] = true;
            dfs(u + 1);
            b[i] = c[u - i] = d[i - u + n] = false;
            a[u][i] = '*';

        }
    }
}
int main()
{
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            a[i][j] = '*';

        }
    }
    dfs(0);

    return 0;
}