Codeforces 284A Cows and Primitive Roots [模拟题]

题目链接：

http://codeforces.com/problemset/problem/284/A

水题水过去了。

#include<iostream>#include<fstream>#include<map>#include<vector>#include<string>#include<memory.h>#include<cmath>#include<algorithm>#include<queue>#define Min(a,b) (a<b?a:b)#define Max(a,b) (a>b?a:b)#define Abs(a) (a>0?(a):-(a))#define llong long long intusing namespace std;const int N=2005,M=100005,inf=0x7fffffff;int n,m;int main(){//freopen("1.txt","r",stdin);while(scanf("%d",&n)!=EOF){int ans=0;for(int i =1;i<n;i++){bool flag =true;int now = 1;for(int j=1;j<n-1;j++){now = (now*i)%n;if(now==1){flag=false;break;}}now = (now*i)%n;if(now != 1){flag=false;}if(flag)  ans++;}printf("%d\n",ans);}return 0;}