[LeetCode] Sqrt(x)

class Solution 
{
public:
	int mySqrt(int x) 
	{
		int s = 0, e = x;
		int ans = 0;

		while (s <= e)
		{
			long long mid = (s + e) / 2;

			if (mid * mid > x)
				e = mid - 1;

			else
			{
				ans = mid;
				s = mid + 1;
			}
		}
		return ans;
	}
};