import java.util.concurrent.*;
import java.util.concurrent.locks.*;


class HovedprogramUke12{

    public static void main(String[] args) {

        int arrayStrl = 0;
        int tallPrTraad = 0;

        try {
            arrayStrl = Integer.parseInt(args[0]);
            tallPrTraad = Integer.parseInt(args[1]);
        }
        catch(Exception e){
            System.out.println("Noe gikk galt! husk strl p? array som argument.");
            System.exit(-1);
        }

        if (arrayStrl % tallPrTraad != 0){
            System.out.println("Send med et tall som g?r opp i 100!");
            System.exit(-1);
        }

        System.out.println("\nOppretter array! (strl: "+arrayStrl+" tall per tr?d: "+tallPrTraad+")");

        int[] liste = new int[arrayStrl];
        for (int i = 0; i < arrayStrl; i++){
            liste[i] = (int) (Math.random() * 1000000); //returnere tall mellom 0 og 1 000 000;
        }

        System.out.println("ferdig med ? lage array!");

        int antallTraader = arrayStrl / tallPrTraad;



        //oppretter en CountDownLatch (barriere) og monitoren v?r.
        CountDownLatch barriere = new CountDownLatch(antallTraader);
        MinMonitor monitor = new MinMonitor();

        //starter tr?den som skal finne det aller minste tallet
        FinnMinsteTallHele oppgave = new FinnMinsteTallHele(monitor, barriere);
        Thread traad = new Thread(oppgave);
        traad.start();

        //starter alle tr?dene som finner det minste tallet i en delmengde av arrayet.
        for (int i = 0; i < antallTraader; i++){
            FinnMinsteTallDel oppgave2 = new FinnMinsteTallDel(liste, i*tallPrTraad, ((i+1)*tallPrTraad), monitor, barriere);
            Thread traad2 = new Thread(oppgave2);
            traad2.start();
        }

        System.out.println("Alle tr?der er startet!");
    }
}


class FinnMinsteTallDel implements Runnable{

    private int[] liste;
    private int start;
    private int slutt;
    private int minsteTall;
    private MinMonitor monitor;
    private CountDownLatch barriere;

    public FinnMinsteTallDel(int[] liste, int start, int slutt, MinMonitor monitor, CountDownLatch barriere){
        this.liste = liste;
        this.start = start;
        this.slutt = slutt;
        this.monitor = monitor;
        this.barriere = barriere;
        minsteTall = liste[start];
    }

    public void run(){

        for (int i = start; i < slutt; i++){
            if (liste[i] < minsteTall){
                minsteTall = liste[i];
            }
        }
        monitor.settMinsteTall(minsteTall);
        barriere.countDown();
    }
}


class FinnMinsteTallHele implements Runnable{

    MinMonitor monitor;
    CountDownLatch barriere;

    public FinnMinsteTallHele(MinMonitor monitor, CountDownLatch barriere){
        this.monitor = monitor;
        this.barriere = barriere;
    }

    public void run(){

        System.out.println("HENTER MINSTE TALL!");
        //long start = System.currentTimeMillis();
        try{
            barriere.await();
        }
        catch(InterruptedException e){
            System.out.println("noe gikk galt!");
        }

        int minsteTall = monitor.hentMinsteTall();
        System.out.println("FIKK MINSTE TALL: " + minsteTall);
        //long totalTid = System.currentTimeMillis() - start;
        //System.out.println("TOTAL TID = " + totalTid/1000F + " sekunder!");
    }
}


class MinMonitor{

    int minsteTall;
    Lock laas = new ReentrantLock();

    public MinMonitor(){
        minsteTall = 10000001;
    }

    public void settMinsteTall(int tall){
        laas.lock();
        try{
            if (tall < minsteTall){
                minsteTall = tall;
            }
        }
        finally{
            laas.unlock();
        }
    }

    public int hentMinsteTall(){
        return minsteTall;
    }
}