HDU 3547 DIY Cube——Polya

题意：

用n种颜色染立方体的8个角，问有多少种不同的方法

思路：

共有24种置换，全部写出即可得到结果6x^2+17x^4+x^8

import java.io.*;
import java.math.*;
import java.util.*;

public class Main {
  public static void main(String [] args) {
    Scanner cin = new Scanner(new BufferedInputStream(System.in));
    int T;
    T = cin.nextInt();
    BigInteger x;
    for (int kase = 1; kase <= T; kase++) {
      x = cin.nextBigInteger();
      BigInteger ans;
      BigInteger temp1 = x;
      BigInteger temp2 = x;
      BigInteger temp3 = x;
      temp1 = temp1.multiply(x);
      temp1 = temp1.multiply(new BigInteger("6"));
      for (int i = 0; i < 3; i++) temp2 = temp2.multiply(x);
      temp2 = temp2.multiply(new BigInteger("17"));
      for (int i = 0; i < 7; i++) temp3 = temp3.multiply(x);
      ans = temp1.add(temp2).add(temp3);
      ans = ans.divide(new BigInteger("24"));
        System.out.printf("Case %d: ", kase);
        String s = ans.toString();
        int len = s.length();
        if (len <= 15) System.out.println(s);
        else {
          for (int i = 15; i >= 1; i--) System.out.printf("%c", s.charAt(len-i));
          System.out.println();
        }
    }
    cin.close();
  }
}