Pow(x,n).txt

class Solution {
public:
    double pow(double x, int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        bool pos = !(n < 0);
        unsigned p = pos?n:-(double)n;
        double ret = 1;
        while (p > 0) {
            ret = (p & 1)?x*ret:ret;
            x *= x;
            p >>= 1;
        }
        return pos?ret:1/ret;   
    }
};