-----Main.cpp------

#pragma once
#include <iostream>
#include <string>
#include <vector>
#include "Timespan.h"
using namespace std;

int main()
{
    int n;
    cin >> n;

    vector<Timespan> times;

    for(int i = 0; i < n; i++)
    {
        int d, m, h, s;
        cin >> d >> h >> m >> s;
        times.push_back(Timespan(d, h, m, s));
    }

    for(int i = 0; i < n; i++)
    {
        for(int j = i+1; j < n; j++)
        {
            if(times[i] > times[j])
            {
                Timespan tmp = times[i];
                times[i] = times[j];
                times[j] = tmp;
            }
        }
    }

    for(int i = 0; i < n; i++)
        cout << times[i] << endl;

    return 0;

}

-----Timespan.cpp------

#include "Timespan.h"

Timespan::Timespan()
{
}

Timespan::Timespan(int days, int hours, int minutes, int seconds)
{
    this->days = days;
    this->hours = hours;
    this->minutes = minutes;
    this->seconds = seconds;
}

Timespan::~Timespan()
{
}

bool Timespan::operator >(const Timespan& other)
{
    if (days > other.days) return true;
    else if (days == other.days && hours > other.hours) return true;
    else if (days == other.days && hours == other.hours && minutes > other.minutes) return true;
    else if (days == other.days && hours == other.hours && minutes == other.minutes && seconds > other.seconds) return true;
    else return false;
}

ostream& operator <<(ostream& izlaz, Timespan other)
{
    int ukupno, dani, sati, minute, sekunde;

    dani = other.days * 86400;
    sati = other.hours * 3600;
    minute = other.minutes * 60;
    ukupno = dani + sati + minute + other.seconds;

    dani = ukupno / 60 / 60 / 24;
    sati = (ukupno / 60 / 60) % 24;
    minute = (ukupno / 60) % 60;
    sekunde = ukupno % 60;

    if (dani > 0) izlaz << dani << "d ";
    if (sati > 0) izlaz << sati << "h ";
    if (minute > 0) izlaz << minute << "min ";
    if (sekunde > 0) izlaz << sekunde << "sec";

    return izlaz;
}

-----Timespan.h---------

#pragma once
#include <iostream>
#include <string>
#include <vector>
using namespace std;

class Timespan
{

private:

    int days, hours, minutes, seconds;

public:

    Timespan();
    Timespan(int days, int hours, int minutes, int seconds);
    ~Timespan();

    bool operator >(const Timespan& other);
    friend ostream& operator <<(ostream& izlaz, Timespan other);

};