leetcode---powx-n---dfs

Implement pow(x, n).

class Solution {public:    double pow(double x, int n)     {        if(n == -2147483648)            return 1.0/(x*pow(x, -n-1));         else if(n == 0)            return 1;          else if(n < 0)            return 1.0/pow(x, -n);         else if(n % 2 == 0)        {              double temp = pow(x, n/2);              return temp * temp;          }         else            return x * pow(x, n-1);      }};