剑指offer 数值的整数次方

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class Solution {
public:
    double Power(double base, int exponent) {
        int isOdd;
        if(0.0==base)return 0;
        if(exponent>0)
        {}
        else if(exponent<0)
        {
            exponent=-exponent;
            base=1.0/base;
        }
        else
            return 1;
          
        if(exponent==1)return base;
          
        if(exponent &0x01 )isOdd=1;//指数是奇数
        int times;
        if(isOdd)
            times=log(exponent-1)/log(2);
        else
            times=log(exponent)/log(2);
          
        double result=base;
        while(times--)
        {
            result=result*result;
        }
        if(isOdd)
            result=result*base;
          
        return result;
    }
};
posted @ 2016-03-16 21:08  copperface  阅读(139)  评论(0)  编辑  收藏  举报