Очередь на зачёт

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <conio.h>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <queue>
#include <set>
#include <stack>

using namespace std;

typedef long long ll;

struct pep
{
    ll t1, t2, t3;
};

bool d(pep p1, pep p2)
{
    return p1.t1 < p2.t1;
}

int main()
{
    ll n;
    cin >> n;
    ll mintime=-1000, alltime=0;
    vector<pep>all;
    pep prom;
    for (int i = 1; i <= n; i++)
    {
        cin >> prom.t1 >> prom.t2 >> prom.t3;
        all.push_back(prom);
    }

    sort(all.begin(), all.end(), d);

    for (int i = 0; i < all.size(); i++)
    {
        if (all[i].t1 > alltime)
            alltime = all[i].t1;
        alltime += all[i].t2;
        ll badtime = alltime - all[i].t3;
        if (mintime < badtime)
            mintime = badtime;
    }

    if (mintime >= 0)
        cout << mintime;
    else
        cout << 0;
    _getch();
    return 0;
}