LeetCode-Pow

class Solution {
public:
double pow(double x, int n) {
if(n==1)return x;
else if(n==-1)return 1/x;
else if(n==0)return 1;
else{
bool flag=n>0;
if(!flag)n=-n;
double ret=1;
int bit=0x40000000;
for(int i=0;i<31;i++){
if(n&bit){
ret=ret*ret*x;
}
else{
ret=ret*ret;
}
bit/=2;
}
if(!flag)return 1/ret;
return ret;
}
// Start typing your C/C++ solution below
// DO NOT write int main() function

}
};