A_Alexey_and_Train.cpp

#include <bits/stdc++.h>

using namespace std;

#define ll long long

int main()
{
    int t;
    cin >> t;
    while (t--)
    {
        int n;
        cin >> n;

        int ari[n + 1] = {0};
        int dep[n + 1] = {0};

        for (int i = 1; i < n + 1; i++)
        {
            cin >> ari[i] >> dep[i];
        }

        int tm[n + 1];

        for (int i = 0; i < n; i++)
            cin >> tm[i];

        ll arrival = 0, previousDeparture = 0;

        for (int i = 1; i <= n; i++)
        {
            int traveltime = abs(ari[i] - dep[i - 1]);

            arrival = previousDeparture + (traveltime + tm[i - 1]);

            int wait = abs(ari[i] - dep[i]);

            wait = (double)ceil(wait / 2.00);

            previousDeparture = arrival + wait;
            previousDeparture = max(previousDeparture, (ll)dep[i]);
        }
        cout << arrival << endl;
    }
}