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 become2 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 从1乘到n-1模n的结果。
只要判断n是否是素数，如果是就输出n-1,否则输出0。n=4，不满足这规律，要特判。
1 #include<cstdio>
2 #include<cstring>
3 #include<map>
4 #include<cmath>
5 using namespace std;
6 int zj[100000];
7 int ssb[100000];
8 int pn;
9 void p()
10 {
11 int i,j;
12 zj[1]=0;
13 zj[0]=0;
14 pn=0;
15 for (i=2;i<=100000;i++)
16 {
17 if (!zj[i]) ssb[pn++]=i;
18 for (j=0;j<pn;j++)
19 {
20 if (i*ssb[j]>100000) break;
21 zj[i*ssb[j]]=1;
22 if (i%ssb[j]==0) break;
23 }
24 }
25 }
26 int main()
27 {
28 p();
29 int n,m,t,i,flag;
30 scanf("%d",&t);
31 while (t--)
32 {
33 flag=0;
34 scanf("%d",&n);
35 if (n==3||n==4) {printf("2\n");continue;}
36 if (n<=100000)
37 {
38 if (zj[n]) printf("0\n");
39 else printf("%d\n",n-1);
40 continue;
41 }
42 flag=0;
43 for (i=0;i<pn;i++)
44 {
45 if (ssb[i]*ssb[i]>n||flag) break;
46 if (n%ssb[i]==0) flag=1;
47 }
48 if (flag) printf("0\n");
49 else printf("%d\n",n-1);
50 }
51 }
11