0231. Power of Two | LeetCode Cookbook

[halfrost]

https://books.halfrost.com/leetcode/ChapterFour/0200~0299/0231.Power-of-Two/

[hanlins]

判断是不是等于lowbit：

func isPowerOfTwo(n int) bool {
    if n <= 0 {
        return false
    }
    lowbit := n & (-n)
    return lowbit == n
}