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.
pow(x, 0.5) in c++ or x ** 0.5 in python.Example 1:
Input: x = 9
Output: 3Example 2:
Input: x = 13
Output: 3Constraints:
0 <= x <= ((2^31)-1)