3827. Count Monobit Integers

You are given an integer n.

An integer is called Monobit if all bits in its binary representation are the same.

Return the count of Monobit integers in the range [0, n] (inclusive).

class Solution {
public:
    int countMonobit(int n) {
        int res = 1;
        for(int i = 1; i <= n; i = i * 2 + 1) res++;
        return res;
    }
};