Leetcode: Sqrt(x)

class Solution 
{
public:
    int mySqrt(int x) 
    {
        if (x < 2) return x;

        int left = 1;
        int right = x / 2;
        int result;

        while (left <= right)
        {
            int middle = (left + right) / 2;
            if (x / middle < middle)
                right = middle - 1;
            else if (x / middle > middle)
            {
                left = middle + 1;
                result = middle;
            }
            else return middle;
        }
        return result;
    }
};