50. Pow(x, n)

#code


class Solution {
public:
    double myPow(double x, int n) {
        double res = 1.0;
        long nn = n;
        if(nn < 0) nn = -1 * nn;
        while(nn){
            if(nn % 2){
                res = res * x;
                nn = nn - 1;
            }
            else{
                x = x * x;
                nn = nn/2;
            }
        }
        if(n < 0) res = (double)(1.0)/(double)(res);
        return res;
    }
};