LeetCode——050

/*
50. Pow(x, n) My Submissions QuestionEditorial Solution
Total Accepted: 88936 Total Submissions: 319149 Difficulty: Medium
Implement pow(x, n).

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*/

/*
解题思路：
使用二分思想求n次方，特殊情况 n=0 n为正数 n为负数
*/

class Solution {
public:
    double myPow(double x, int n) {
        //利用二分法思想（分治）
        int i=n/2;
        //如果n==0直接返回1
        if(n==0)return 1;
        //先计算一半
        double t=myPow(x,i);
        //如果是偶数
        if(n%2==0) return t*t;
        else {
            //奇数且大于0
            if(n>0)return t*t*x;
            //奇数且小于0
            else return t*t/x;
        }

    }
};