231. Power of Two
Given an integer n, return true if it is a power of two. Otherwise, return false.
An integer n is a power of two, if there exists an integer x such that n == 2x.
Example 1:
Input: n = 1 Output: true Explanation: 20 = 1
Example 2:
Input: n = 16 Output: true Explanation: 24 = 16
Example 3:
Input: n = 3 Output: false
Example 4:
Input: n = 4 Output: true
Example 5:
Input: n = 5 Output: false
Constraints:
-231 <= n <= 231 - 1
Rust Solution
struct Solution;
impl Solution {
fn is_power_of_two(n: i32) -> bool {
if n <= 0 {
return false;
}
n & (n - 1) == 0
}
}
#[test]
fn test() {
assert_eq!(Solution::is_power_of_two(1), true);
assert_eq!(Solution::is_power_of_two(16), true);
assert_eq!(Solution::is_power_of_two(218), false);
}
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