POJ 2409 let_it_bead

把以前的题目又做了一遍，复习了一下波利亚定理

#include<stdio.h>#include<math.h>double c;int s;int gcd(int a,int b) {//求最大公约数if (b==0) return a;else return gcd(b,a%b);}int main() {#ifndef ONLINE_JUDGEfreopen("in.txt","r",stdin);#endifdouble ans=0;int i;while(scanf("%lf%d",&c,&s)) {if (c==0 && s==0) break;ans=0;for(i=0;i<s;i++) {ans+=pow(c,gcd(s,i));//旋转i格}if (s%2==0) {//翻转ans+=s/2*pow(c,s/2+1);ans+=s/2*pow(c,s/2);}else {ans+=s*pow(c,s/2+1);}ans=ans/(2*s);printf("%.0lf\n",ans);}return 0;}