Sum of ones

input/code.cpp: In function 'void Test()':
input/code.cpp:9:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     freopen("temp\\in.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long LL;

const int N=1005;

void Test()
{
    freopen("temp\\in.txt", "r", stdin);
}
LL f[N], ans;
bool one[N];
int main()
{
    // Test();
    LL n;
    cin>>n; 

    f[1] = 1;
    for(int i=2; i<=60; i++)
    {
        f[i] = (f[i-1] << 1) + (1LL<<(i-1));
        // cout << f[i] <<endl;
    }

    int k=0, now=0;
    while(n)
    {
        one[++k] = n%2;
        n/=2; 
    }

    for(int i=k; i>=1; i--)
    {
        if(one[i])
        {
            // place 0
            ans += f[i-1] + now*(1LL<<(i-1));
            // place 1
            now ++;
        }
    }

    cout<<ans+now;

    return 0;
}

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: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED