Time Limit:1500MS Memory Limit:262144KB 64bit IO Format:%I64d & %I64u
Description
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 following T lines, each line contains an integer n, according to the description.
T \leq {10}^{5},2 \leq n \leq {10}^{9}
Output
Sample Input
2
3
10
Sample Output
2
0
思路：用 long long 直接暴力打个表可以看到21以内的结果， 5以前的没什么规律， 5以后的只要是素数答案是n-1， 不是素数答案都是0。n的取值范围十的九次方， 一般这种题都是水题。 代码：
#include<stdio.h>
#include<string.h>
#include<math.h>
#define N 110
void judge(int n)//判断是否是素数。
{
int i, k, f = 0;
k = (int)sqrt(n);
for(i = 2; i <= k; i++)
{
if(n % i == 0)
{
printf("%d\n", 0);
f = 1;
break;
}
}
if(f ==0)
printf("%d\n", n-1);
}
int main()
{
int t, n;
scanf("%d", &t);
while(t--)
{
scanf("%d", &n);
if(n == 2)
printf("1\n");
else if(n == 3 || n == 4)
printf("2\n");
else if( n == 5)
printf("4\n");
else
{
judge(n);
}
}
return 0;
}