#include <iostream>
using namespace std;

void findWaitingTime(int processes[], int n, int bt[], int wt[], int at[], int quantum, int firstExecTime[])
{
    int rem_bt[n];
    for (int i = 0; i < n; i++)
        rem_bt[i] = bt[i];

    int t = 0;
    int done = 0;

    while (done < n)
    {
        bool progress = false;

        for (int i = 0; i < n; i++)
        {
            if (at[i] <= t && rem_bt[i] > 0)
            {
                progress = true;

                if (firstExecTime[i] == -1) {
                    firstExecTime[i] = t;
                }

                if (rem_bt[i] > quantum)
                {
                    t += quantum;
                    rem_bt[i] -= quantum;
                }
                else
                {
                    t += rem_bt[i];
                    wt[i] = t - bt[i] - at[i];
                    rem_bt[i] = 0;
                    done++;
                }
            }
        }

        if (!progress)
            break;
    }
}

void findTurnAroundTime(int processes[], int n, int bt[], int wt[], int tat[])
{
    for (int i = 0; i < n; i++)
        tat[i] = bt[i] + wt[i];
}

void findAvgTime(int processes[], int n, int bt[], int at[], int quantum)
{
    int wt[n], tat[n], total_wt = 0, total_tat = 0, total_resp = 0;
    int firstExecTime[n];

    for (int i = 0; i < n; i++) {
        firstExecTime[i] = -1;
    }

    findWaitingTime(processes, n, bt, wt, at, quantum, firstExecTime);

    findTurnAroundTime(processes, n, bt, wt, tat);

    cout << "PN\tAT\tBT\tWT\tTAT\tRT\n";

    for (int i = 0; i < n; i++)
    {
        total_wt += wt[i];
        total_tat += tat[i];
        total_resp += (firstExecTime[i] - at[i]);
        cout << " " << i + 1 << "\t" << at[i] << "\t" << bt[i] << "\t" << wt[i] << "\t" << tat[i] << "\t" << (firstExecTime[i] - at[i]) << endl;
    }

    cout << "Average waiting time = " << (float)total_wt / (float)n << endl;
    cout << "Average turnaround time = " << (float)total_tat / (float)n << endl;
    cout << "Average response time = " << (float)total_resp / (float)n << endl;
}

int main()
{
    int n;

    cout << "Enter the number of processes: ";
    cin >> n;

    int processes[n], burst_time[n], arrival_time[n];

    for (int i = 0; i < n; i++)
    {
        processes[i] = i + 1;

        cout << "Enter arrival time, burst time for Process " << i + 1 << ": ";
        cin >> arrival_time[i] >> burst_time[i];
    }

    int quantum;
    cout << "Enter time quantum: ";
    cin >> quantum;

    findAvgTime(processes, n, burst_time, arrival_time, quantum);

    return 0;
}