Sqrt(x)

You are 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 = 9

Output: 3

Example 2:

Input: x = 13

Output: 3

Constraints:

• 0 <= x <= ((2^31)-1)