[LeetCode] Pow(x, n) 解题报告

Implement pow( x,  n).

» Solve this problem

[解题思路]
二分法，注意n<0的情况。

[Code]

1:    double power(double x, int n)  
2:    {  
3:       if (n == 0)  
4:         return 1;  
5:       double v = power(x, n / 2);  
6:       if (n % 2 == 0)  
7:         return v * v;  
8:       else  
9:         return v * v * x;  
10:     }  
11:     double pow(double x, int n) {  
12:       // Start typing your C/C++ solution below  
13:       // DO NOT write int main() function  
14:       if (n < 0)  
15:         return 1.0 / power(x, -n);  
16:       else  
17:         return power(x, n);      
18:     }