class Solution {
public:
    double Power(double base, int exponent) {
        typedef long long LL;
        double res = 1, t = base;
        long long int m = abs(LL(exponent));
        for(; m; m >>= 1){
            if(m & 1) res *= t;
            t *= t;
        }
        if(exponent < 0)
            res = 1 / res;
        return res;
    }
};