Round Robin Scheduling (pre-emptive)

round_robin.cpp

#include<iostream>
#include<fstream>
#include<deque>
#include <algorithm>

using namespace std;

//input
/*
6 2 //totalProcess timeQuantum
0 4
1 5
2 2
3 1
4 6
6 3
*/

int main(){
    int totalProcess, timeQuantum;

    //input from file
    ifstream cin("input_4.txt");
    cin>>totalProcess>>timeQuantum;

    int arrivalTime[totalProcess];
    int burstTime[totalProcess];
    int scheduler[totalProcess*2];
    deque<int> processQueue;

    for(int i=0;i<totalProcess;i++){
        cin>>arrivalTime[i]>>burstTime[i];
    }

    //initialize queue
    int currentProcess = 0;
    processQueue.push_back(currentProcess);

    int index = 0;
    int currentTime = 0;
    int pIndex = 0;

    while(!processQueue.empty()){
        //add into scheduler
        scheduler[index] = processQueue.front();
        currentProcess = scheduler[index];
        processQueue.pop_front();
        if(burstTime[currentProcess] > timeQuantum){
            burstTime[currentProcess] -= timeQuantum;
            currentTime += timeQuantum;
        } else {
            currentTime += burstTime[currentProcess];
            burstTime[currentProcess] = 0;
        }

        for(int i=currentProcess + 1;i<totalProcess;i++){
            int inScheduler = 0;
            for(int j=0;j<index;j++){
                if(scheduler[j] == i){
                    inScheduler = 1;
                }
            }
            if(arrivalTime[i] <= currentTime && inScheduler == 0 && find(processQueue.begin(), processQueue.end(), i) == processQueue.end()){
                //cout<<"push "<<i<<endl;
                processQueue.push_back(i);
            }
        }

        if(burstTime[currentProcess] > 0){
            processQueue.push_back(currentProcess);
        }

        index++;
    }


    for(int i=0;i<index;i++){
        cout<<"P:"<<scheduler[i]+1<<endl;
    }

    /*
    for(int i=0;i<totalProcess;i++){
        cout<<burstTime[i]<<endl;
    }
    */


    //test print
    /*
    for(int i=0;i<totalProcess;i++){
        cout<<arrivalTime[i]<<" "<<burstTime[i]<<endl;
    }
    */
}