README.md

231. Power of Two

Given an integer, write a function to determine if it is a power of two.

Example 1:

Input: 1
Output: true
Explanation: 20 = 1

Example 2:

Input: 16
Output: true
Explanation: 24 = 16

Example 3:

Input: 218
Output: false

Solutions (Rust)

1. n & (n - 1)

impl Solution {
    pub fn is_power_of_two(n: i32) -> bool {
        if n <= 0 {
            false
        } else {
            n & (n - 1) == 0
        }
    }
}

2. n / 2

impl Solution {
    pub fn is_power_of_two(n: i32) -> bool {
        if n <= 0 {
            false
        } else if n == 1 {
            true
        } else {
            n % 2 == 0 && Self::is_power_of_two(n / 2)
        }
    }
}