Being Code Expert: Monk and Tasks

Monk A loves to complete all his tasks just before the deadlines for introducing unwanted thrill in his life. But, there is another Monk D who hates this habit of Monk A and thinks it's risky.

To test Monk A, Monk D provided him tasks for N days in the form of an array Array, where the elements of the array represent the number of tasks.

The number of tasks performed by Monk A on an ith day is the number of ones in the binary representation of Arrayi.

Monk A is fed up with Monk D, so to irritate him even more, he decides to print the tasks provided in non-decreasing order of the tasks performed by him each day. Help him out!

Example:

Input:  n = 4, a = [3,4,7,10]
Output: 4 3 10 7

Approach

C++

#include <bits/stdc++.h>
using namespace std;
bool cmp(pair<long long, 
pair<long long, long long>> a, pair<long long, 
pair<long long, long long>> b)
{

    if (a.first == b.first)
        return a.second.first < b.second.first;
    return a.first < b.first;
}
long long count(long long n)
{
    long long res = 0;
    while (n)
    {
        n = n & (n - 1);
        res++;
    }
    return res;
}
int main()
{

    long long n = 4;

    long long a[n] = {3, 4, 7, 10};

    vector<pair<long long, pair<long long, long long>>> v;
    for (long long i = 0; i < n; i++)
    {
        long long cnt = count(a[i]);
        v.push_back(make_pair(cnt, make_pair(i, a[i])));
    }
    sort(v.begin(), v.end(), cmp);
    for (long long i = 0; i < n; i++)
        cout << v[i].second.second << " ";
    cout << "\n";

    return 0;
}