LeetCode: Sqrt(x)

class Solution {
public:
int sqrt(int x) {
long long left = 0, right = x;
while(left <= right){
long long mid = (left + right) / 2;
if(mid*mid == x)return mid;
else if(mid * mid < x)
left = mid+1;
else
right = mid-1;
}
return right;
}
};