69-Sqrt(x).md

69. Sqrt(x) (Python)

Problem

Implement int sqrt(int x).

Compute and return the square root of x.

x is guaranteed to be a non-negative integer.

Example 1:

Input: 4
Output: 2

Example 2:

Input: 8
Output: 2

Explanation: The square root of 8 is 2.82842..., and since we want to return an integer, the decimal part will be truncated.

Solution 1.

利用內建的 math.sqrt() 來計算平方根。最後強制轉型 int 取整數。

• Run Time: 24 ms

import math
class Solution(object):
    def mySqrt(self, x):
        return int(math.sqrt(x))

Solution 2.

• 二元搜尋
• Run Time: ms