69. Sqrt(x)

Given a non-negative integer x, return the square root of x rounded down to the nearest integer. The returned integer should be non-negative as well.

You must not use any built-in exponent function or operator.

• For example, do not use pow(x, 0.5) in c++ or x ** 0.5 in python.

Example 1:

Input: x = 4
Output: 2
Explanation: The square root of 4 is 2, so we return 2.

Example 2:

Input: x = 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since we round it down to the nearest integer, 2 is returned.

def mySqrt(self, x: int) -> int:
	if x == 0:
		return 0
	left, right = 1, x
	while left <= right:
		mid = (left + right) // 2
		if mid * mid == x:
			return mid
		elif mid * mid < x:
			left = mid + 1
		else:
			right = mid - 1
	return right