题意:输入两个数p,a;如果a的p次方对p取余等于a,并且p不是素数,则输出“yes”,否则输出“no”.
这里用到快速幂求余技巧
#include <iostream> #include <stdio.h> using namespace std; bool isprime(long long n){ for (long long i = 2; i*i <= n; i++){ if (n%i == 0) return false; } return true; } long long qmod(long long a, long long r, long long m){ long long res = 1; while (r){ if (r & 1) res = res*a%m; a = a*a%m; r >>= 1; } return res; } int main(){ long long p, a; while (scanf("%I64d%I64d", &p, &a) && p&&a){ if (!isprime(p) && qmod(a, p, p) == a) printf("yes\n"); else printf("no\n"); } return 0; }
原文:https://www.cnblogs.com/jianqiao123/p/10685454.html