HDU5391 Zball in Tina Town（埃拉托斯尼斯判断素数）

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

思路 由素数一个定理 若P是一个素数 那么（P-1）！mod P = P-1；若P是一个合数 那么这个等式结果为0 但4是唯一一个列外需要额外判断；

埃拉托斯尼斯定理：一个和数N在0-N^1/2的区间里必有 一个质数是他的因子；

所以我们可以根据这个定理来判断是不是素数，然后根据第一个定理来输出结果

#include 
#include 
#include 
using namespace std;
int prime[1000005];
bool isPrime[1000005];

void Prime()//打印素数表

{
    int num = 0;
    memset(isPrime,true,sizeof(isPrime));
    isPrime[0] = isPrime[1] = false;
    for(int i=2 ; i<= 1000005; i++){
        if( isPrime[i] ) prime[num++] = i;
        for(int j=0 ; j1000005 ) break;
            isPrime[ i*prime[j] ] = false;
            if( i%prime[j] == 0 ) break;
        }
    }
}
bool check(int n)//判断N是不是素数
{
    int flag = 1;
    for(int i = 0;prime[i]*prime[i]