程序代码：

#include <stdio.h>

static int upperlim, sum; 

void binqueen(int row, int ld, int rd)
{
    int pos, p;
    if(row != upperlim)
    {
        pos = upperlim & ~(row | ld | rd);
        while (pos)
        {
            p = pos & -pos;
            pos -= p;
            binqueen(row+p, (ld+p)<<1, (rd+p)>>1);
        }
    }
    else sum++;
}


int main(int argc, char *argv[])
{
    int n;
    scanf("%d", &n);
    upperlim = (1<<n) - 1;
    binqueen(0, 0, 0);
    printf("%d", sum);
    return 0;
}