HDU 4762 Cut the Cakes(數學題，推公式）

解題思路：

推出的公式為 N  /  （M ^ (N-1) )。要用到高精度

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

public class Main
{      
	static BigInteger gcd(BigInteger a, BigInteger b)
	{
		if(b.equals(BigInteger.ZERO)) return a;
		else return gcd(b, a.mod(b));
	}
	public static void main(String args[])
	{
		Scanner cin = new Scanner(System.in);
		int T, N, M;
		T = cin.nextInt();
		for(int i=1;i<=T;i++)
		{
			M = cin.nextInt();
			N = cin.nextInt();
			BigInteger tmp1 = BigInteger.valueOf(N);
			BigInteger tmp2 = BigInteger.valueOf(M).pow(N-1);
			BigInteger t = gcd(tmp1, tmp2);
			tmp1 = tmp1.divide(t);
			tmp2 = tmp2.divide(t);
			System.out.println(tmp1 + "/" + tmp2);
		}
	}
}