SGU112 a^b - b^a

SGU112 a^b - b^a

题目大意

输入$a$和$b$，输出$a^b - b^a$的值

算法思路

直接计算，使用Java的BigInteger类可以避免手动实现高精度运算

时间复杂度: $O(1)$

代码

/**
 * Copyright (c) 2015 Authors. All rights reserved.
 * 
 * FileName: 112.java
 * Author: Beiyu Li <sysulby@gmail.com>
 * Date: 2015-05-22
 */
import java.io.*;
import java.math.*;
import java.text.*;
import java.util.*;

public class Solution
{
    public static void main(String args[])
    {
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        int a = cin.nextInt(), b = cin.nextInt();
        System.out.println(BigInteger.valueOf(a).pow(b).subtract(
                    BigInteger.valueOf(b).pow(a)));
    }
}

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