Pow(x, n)

class Solution {
public:
    double myPow(double x, int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(n<0)
        {
            if(n==INT_MIN)
                return 1.0 / (myPow(x,INT_MAX)*x);
            else
                return 1.0 / myPow(x,-n);
        }
        if(n==0)
            return 1.0;
        double ans = 1.0 ;
        for(;n>0; x *= x, n>>=1)
        {
            if(n&1>0)
                ans *= x;
        }
        return ans;
    }
};