Sum of ones

#include<vector>
#include<iostream>
#define ll long long
using namespace std;
ll getnextBit(ll n){
        ll m = 0;
    while (n > 1) {
        n = n >> 1;
        m+=1;
    }
    return m;
}
ll getmostBit(ll n, ll m){
        ll tmp = 1 << m;
    while (n < tmp) {
        tmp = tmp >> 1;
        m-=1;
    }
    return m;
}
ll func(ll n){

    if (n == 0)
        return 0;

    ll m = getmostBit(n, getnextBit(n));
    if (n == (1LL << (m + 1)) - 1)
        return (m + 1) * (1 << m);

    n = n - (1LL << m);
    return (n + 1) + func(n) + m * (1LL << (m - 1));
}
int main(){
    int n;
    cin >> n;
    cout<<func(n)<<endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: WRONG ANSWER

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: WRONG ANSWER