Leetcode 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

Algorithm

Using bit operations, add one bit to the left each time until a number not less than n is found.

Code

class Solution:
    def smallestNumber(self, n: int) -> int:
        ans, bits = 1, 2
        while ans < n:
            ans += bits
            bits <<= 1
        
        return ans