POJ1286 Necklace of Beads(Polya定理)
Time Limit: 1000MS | Memory Limit: 10000K | |
Total Submissions: 9359 | Accepted: 3862 |
Description
Beads of red, blue or green colors are connected together into a circular necklace of n beads ( n < 24 ). If the repetitions that are produced by rotation around the center of the circular necklace or reflection to the axis of symmetry are all neglected, how many different forms of the necklace are there?
![](http://poj.org/images/1286_1.jpg)
![](http://poj.org/images/1286_1.jpg)
Input
The input has several lines, and each line contains the input data n.
-1 denotes the end of the input file.
-1 denotes the end of the input file.
Output
The output should contain the output data: Number of different forms, in each line correspondent to the input data.
Sample Input
4 5 -1
Sample Output
21 39
Source
哈哈我是来骗访问量的。这题和上一题一毛一样
只不过需要把颜色数改为$3$然后换成LLd
上一篇:https://www.cnblogs.com/zwfymqz/p/9294983.html
#include<algorithm> #include<iostream> #include<cstdio> #define int long long using namespace std; int C = 3, N; int fastpow(int a, int p) { int base = 1; while(p) { if(p & 1) base = base * a; a = a * a; p >>= 1; } return base; } main() { while(cin >> N) { if(N == -1) break; if(N <= 0) {printf("0\n"); continue;} int ans = 0; for(int i = 1; i <= N; i++) ans += fastpow(C, __gcd(i, N)); if(N & 1) ans = ans + N * fastpow(C, (N + 1) / 2); else ans = ans + N / 2 * (fastpow(C, (N + 2) / 2) + fastpow(C, N / 2)); cout << ans / 2 / N << endl; } }
作者:自为风月马前卒
本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。