69. x 的平方根 @Python @Go

原题

https://leetcode.cn/problems/sqrtx/description/

思路

二分查找

复杂度

时间：O(log(n))
空间：O(log(n))

Python代码

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

Go代码

func mySqrt(x int) int {
	l, r := 0, x
	for l <= r {
		mid := (l + r) / 2
		if mid*mid <= x && (mid+1)*(mid+1) > x {
			return mid
		} else if mid*mid < x {
			l = mid + 1
		} else {
			r = mid - 1
		}
	}
	return l
}