342. Power of Four
Given an integer n
, return true
if it is a power of four. Otherwise, return false
.
An integer n
is a power of four, if there exists an integer x
such that n == 4x
.
Example 1:
Input: n = 16 Output: true
Example 2:
Input: n = 5 Output: false
Example 3:
Input: n = 1 Output: true
Constraints:
-231 <= n <= 231 - 1
Follow up: Could you solve it without loops/recursion?
Rust Solution
struct Solution;
use std::i32;
impl Solution {
fn is_power_of_four(mut n: i32) -> bool {
while n != 0 && n % 4 == 0 {
n /= 4;
}
n == 1
}
}
#[test]
fn test() {
assert_eq!(Solution::is_power_of_four(16), true);
}
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