Zball in Tina TownTime Limit: 3000/1500 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 1356 Accepted Submission(s): 705
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
Source
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題意:
解題思路:計算(n-1)! mod n 的值
AC代碼:威爾遜定理:p是素數 則( p -1 )! ≡ -1 ( mod p )
p不是素數 結果是0. 注意4的情況!
#include <stdio.h> #include <math.h> #include <algorithm> using namespace std; bool is_prime(int n) { if(n==1||n==2) return true; if(!(n&1)) return false; int m=sqrt(n); for(int i=2;i<=m;i++){ if(n%i==0) return false; } return true; } int main() { int t; scanf("%d",&t); while(t--){ int n; scanf("%d",&n); if(n==4){ printf("2\n"); continue; } if(is_prime(n)) printf("%d\n",n-1); else printf("0\n"); } return 0; }