import java.util.*;
import java.io.*;
class PROIRTYWITHPREEMPTION{
	public static void main(String args[]) {
		int sumw = 0, sumt = 0, sumBurst = 0, n, i, j, k, temp, preJobNo, doJob=0;
		double avgWT, turnAT;
		Scanner sc = new Scanner(System.in);
		System.out.println("ENTER NUMBER OF JOBS");
		n = sc.nextInt();
		int burstTime[] = new int[n];
		int waitTime[] = new int[n];
		int priority[] = new int[n];
		int arrival[] = new int[n];
		int jobNo[] = new int[n];
		int finished[] = new int[n];

		System.out.println("Enter burst time, Priority and Arrival time for each job :");
		for (i = 0; i < n; i++) {
			System.out.println("Enter burst time of job "+i+" : ");
			burstTime[i] = sc.nextInt();
			System.out.println("Enter priority of job "+i+" : ");
			priority[i] = sc.nextInt();
			System.out.println("Enter arrival time of job "+i+" : ");
			arrival[i] = sc.nextInt();
			jobNo[i] = i+1;
			sumBurst = sumBurst + burstTime[i];
		}

		int ganntChart[] = new int[sumBurst];

		/* Sorting all the job as per priority time */
		for (i = 0; i < n - 1; i++) {
			for (j = 0; j < n - 1; j++) {
				if (priority[j] > priority[j + 1]) {
					temp = priority[j];
					priority[j] = priority[j + 1];
					priority[j + 1] = temp;

					temp = arrival[j];
					arrival[j] = arrival[j + 1];
					arrival[j + 1] = temp;

					temp = burstTime[j];
					burstTime[j] = burstTime[j + 1];
					burstTime[j + 1] = temp;

					temp = jobNo[j];
					jobNo[j] = jobNo[j + 1];
					jobNo[j + 1] = temp;
				}
			}
		}

		/*printing the input table just for referance */
		System.out.println("JobNo\tBT\tpriority\tarrival");
		for(i=0;i<n;i++){
			System.out.println(jobNo[i]+"\t"+burstTime[i]+"\t"+priority[i]+"\t\t"+arrival[i]);
		}

		/* printing out the gannt chart int form of table */
		doJob = 0;
		System.out.println("Time Unit" + "\t" + "Job Number");
		for (i = 0; i < sumBurst; i++) {

			//get doable jobs as per arrival time
			for(j=0;j<n;j++)
			{
				if(arrival[j]<=i&&burstTime[j]!=0)
				{
					doJob = jobNo[j];
					burstTime[j]--;
					if(burstTime[j]==0)
					{
						finished[j] = i+1;
					}
					break;
				}

			}

			System.out.print(i+"-"+ (i+1) + "\t\t" + doJob);
			ganntChart[i] = doJob;
			System.out.println();
		}

		/*Calculation of Average Wait time */
		sumw = 0;
		for(i=0;i<n;i++){
			for(j=0;j<sumBurst;j++){
				if(ganntChart[j]!=jobNo[i]&&j<finished[i]){
					sumw++;
				}
			}
			sumw = sumw - arrival[i];
		}
		avgWT = sumw * (1.0) / n;

		/*Calculation of Average Turn Around time */
		j=0;
		while(j<n){
			sumt = sumt + finished[j]-arrival[j];
			j++ ;
		}
		turnAT = sumt * (1.0) / n;

		/*printing out the results*/
		System.out.println();
		System.out.println("AVERAGE WAITING TIME =" + avgWT + "\t" + "AVERAGE TURN AROUND TIME=" + turnAT);
	}
}


OUTPUT:


ENTER NUMBER OF JOBS 5
Enter burst time, Priority and Arrival time for each job :
Enter burst time of job 0 : 10
Enter priority of job 0 : 3
Enter arrival time of job 0 :0
Enter burst time of job 1 : 1
Enter priority of job 1 : 1
Enter arrival time of job 1 :1
Enter burst time of job 2 : 2
Enter priority of job 2 : 3
Enter arrival time of job 2 :2
Enter burst time of job 3 : 1
Enter priority of job 3 : 4
Enter arrival time of job 3 :3
Enter burst time of job 4 : 5
Enter priority of job 4 : 2
Enter arrival time of job 4 :4
JobNo	BT	priority	arrival
2	1	1		1
5	5	2		4
1	10	3		0
3	2	3		2
4	1	4		3
Time Unit	Job Number
0-1		1
1-2		2
2-3		1
3-4		1
4-5		5
5-6		5
6-7		5
7-8		5
8-9		5
9-10		1
10-11		1
11-12		1
12-13		1
13-14		1
14-15		1
15-16		1
16-17		3
17-18		3
18-19		4

AVERAGE WAITING TIME =7   	AVERAGE TURN AROUND TIME=10.8