DFS算法解决N皇后问题

#include<iostream>
#include<cmath>
#include<cstring>
using namespace std;
int n, tot = 0;
int col[12] = { 0 };
bool check(int c, int r) {
    for (int i = 0; i < r; i++)
        if (col[i] == c || (abs(col[i] - c) == abs(i - r))) {//qujueduuizhi
            return false;
        }
    return true;
}
void DFS(int r) {
    if (r == n) {
        tot++;
        return;
    }
    for (int c = 0; c < n; c++) {
        if (check(c, r)) {
            col[r] = c;
            DFS(r + 1);
        }
    }
}
int main() {
    int ans[12] = { 0 };
    for (n = 0; n <= 10; n++) {
        memset(col, 0, sizeof(col));
        tot = 0;
        DFS(0);
        ans[n] = tot;
    }
    while (cin >> n) {
        if (n == 0)
            return 0;
        cout << ans[n] << endl;
    }
    return 0;
}