（hdu）5391 Zball in Tina Town

题目链接：http://acm.split.hdu.edu.cn/showproblem.php?pid=5391

Problem Description
Tina Town is a friendly place. People there care about each other.

Tina has a ball called zball. Zball is magic. It grows larger every day. On the first day, it becomes 1 time as large as its original size. On the second day,it will become 2 times as large as the size on the first day. On the n-th day,it will become n times as large as the size on the (n-1)-th day. Tina want to know its size on the (n-1)-th day modulo n.

Input
The first line of input contains an integer T, representing the number of cases.

The following T lines, each line contains an integer n, according to the description.
T≤105,2≤n≤109

Output
For each test case, output an integer representing the answer.

Sample Input
2
3
10

Sample Output
2
0

题意：求（n-1）！对n取模

方法：如果是素数就是n-1，如果不是素数（除了4）都是0，4的结果是2

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <stack>
#include <math.h>
#include <queue>
#include <vector>
using namespace std;
#define N 10010
#define ll long long
#define met(a,b) memset(a,b,sizeof(a));
vector<vector<int> >Q;
int n;
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int f=0;
        scanf("%d",&n);

        if(n==4)///特例
        {
            printf("2\n");
            continue;
        }
        int k=(int)sqrt(n);
        for(int i=2; i<=k; i++)
        {
            if(n%i==0)
            {
                f=1;
                break;
            }

        }

        if(f)
            printf("0\n");
        else
            printf("%d\n",n-1);
    }
    return 0;
}