求助！能问一下大佬们哪里有问题呢

#include<iostream>
#include<cstring>
using namespace std;
int n, a[100], b[100], c[100], d[100];
int ans = 0;
void dfs(int x)
{
    if (x > n)
    {
        ans++;
        if (ans <= 3)
        {
            for (int i = 1; i <= n; i++)
            {
                cout << a[i] << ' ';
            }
            cout << endl;
        }
        return;
    }
    for (int i = 1; i <= n; i++)
    {
        if (b[x] == 0 && c[x + i] == 0 && d[x-i+n] == 0)
        {
            a[x] = i;
            b[x] = 1, c[x + i] = 1, d[i- x +n] = 1;
            dfs(x + 1);
            b[x] = 0, c[x + i] = 0, d[i - x + n] = 0;
        }
    }
}
int main()
{
    cin >> n;
    dfs(1);
    cout << ans;
    return 0;
}