FWNX - power(double x,int n) - C++version

最新推荐文章于 2024-11-16 14:12:17 发布

kingoverlord

最新推荐文章于 2024-11-16 14:12:17 发布

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分类专栏：数据结构文章标签： c++ power 算法

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本文介绍了一种使用递归实现快速幂运算的方法，并考虑了不同情况下的整数指数运算，包括正数、负数及偶数、奇数的情况。通过递归计算一半的幂次再进行平方或乘以基数的方式加速计算过程。

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class Solution {
public:
    double pow(double x, int n) {
        if (n == 0) return 1;	 //	if n == 0; return 1;


	double half = pow(x, n/2);


	if (n % 2 == 0) return half * half;	//if n is even return power(x,n/2) *  power(x,n/2)
	else
	if(n%2 ==1 || n%2 == -1)
	{
	    if(n > 0) return half*half*x;
	    if(n<0)
	    {
	        return half*half*(1/x);
	    }
	}
	
    }
};

1 = when you met the int n we must consider this in the four case :

1.1 odd negative

1.2 odd positive

1.3 even positive

1.4 even positive

2 = wonderful recursive

calculate the half at first and then use this half to calculate the whole

but we must give the base value before the calculating of half or dead loop

3 = the negative odd % 2 = -1

the positive odd % 2 = 1

the negative and positive even %2 = 0