"""
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):
        """
        :type x: int
        :rtype: int
        """

        """
        # 采用二分法
        low, high = 0, x
        while(low <= high):
            mid = int((low + high) / 2)
            if mid*mid > x :
                high = mid - 1
            elif mid*mid < x:
                low = mid + 1
            else:
                return mid
        return low - 1
        """
        # 采用牛顿迭代法
        r = x
        while r * r > x:
            r = int((r + x / r) / 2)
        print(r)
        return r

if __name__ == '__main__':
    x = 10
    solution = Solution()
    solution.mySqrt(x)