leetcode[50]Pow(x, n)
Implement pow(x, n).
class Solution { public: double pow(double x, int n) { if(n==0)return 1.0; if(n<0) { double half=pow(x,-n/2); if(-n%2)return 1/(half*half*x); else return 1/(half*half); } return 1.0/pow(x,-n); if(n>0) { double half=pow(x,n/2); if(n%2)return half*half*x; else return half*half; } } };