3370 - Smallest Number With All Set Bits

problem

You are given a positive number n.

Return the smallest number x greater than or equal to n, such that the binary representation of x contains only set bits

Example 1:

Example 2:

Example 3:

Constraints:

• 1 <= n <= 1000

submission

impl Solution {
    pub fn smallest_number(n: i32) -> i32 {
        //        | the first set bit
        //    0000101..0
        // -> 0000111..1
        // -> 0001000..0 - 1
        (1 << (32 - n.leading_zeros())) - 1
    }
}