class Solution { public: double pow(double x,int n) { if(n<0)return 1.0/power(x,-n); return power(x,n); } double power(double x, int n) { if(n == 0) return 1; double temp = power(x, n/2); if(n % 2 == 0) return temp * temp; else return temp * temp * x; } };
原文:http://blog.csdn.net/wdkirchhoff/article/details/41703049