/**
knakul853
**/
class Solution {
public:
    double myPow(double x, int n) {

        long p = (long)n;

        if( n < 0 )
            return 1.0 / binPow(x, -p);
        else
            return binPow(x, p);

    }

    double binPow( double x, long p )
    {
        double res = 1.0;

        while( p )
        {
            if( p&1 )
                res = res * x;
            p = p/2;
            x = x * x;
        }

        return res;
    }
};