sqrtx.py

'''

Implement int sqrt(int x).

Compute and return the square root of x, where x is guaranteed to be a non-negative integer.

Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.

Example 1:

Input: 4
Output: 2
Example 2:

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since
             the decimal part is truncated, 2 is returned.

'''


class Solution:
    def mySqrt(self, x: int) -> int:
        l,r = 0,x
        while l <= x:
            mid = l + (r-l)//2
            if mid ** 2 <= x and (mid +1) ** 2 > x:
                return mid
            elif mid ** 2 < x :
                l = mid + 1
            else:
                r = mid - 1