package blatt14;


public class FindMax extends Thread {

    private final boolean isMaster;
    private final int start; // Bereichsanfang 
    private final int size; // Bereichsgroesse 
    private final int[] data; // Stores the result of this thread: 
    public int max = Integer.MIN_VALUE; // Constructor for master. 

    public FindMax(int[] data, int size) {
        this.data = data;
        this.start = 0;
        this.size = size;
        isMaster = true;
    }

    // Constructor for slave.
    public FindMax(int[] data, int start, int size) {
        this.data = data;
        this.start = start;
        this.size = size;
        this.isMaster = false;
    }

    public void run() {
        try { // Handles all possible InterruptedExceptions 
            if (isMaster) { // Code for master 
                System.out.println("master");
                
                int amount = data.length/size;
                FindMax[] t = new FindMax[amount];
                
                for (int i = 0; i < amount; i++) {
                    t[i] = new FindMax(data, i*size, size);
                    t[i].start();
                }                 
                
                for (int i = amount*size; i < data.length; i++) {
                    if (data[i] > max) {
                        max = data[i];
                    }
                }
                             
                for (int i = 0; i < amount; i++) {
                    t[i].join();
                }
                
                for (FindMax c : t) {
                    if (c.max > max)
                        max = c.max;
                }
            } else { // Code for slaves
                System.out.println("slave , " + start + " to " + (start + size - 1));
            
                for (int i = start; i < start+size; i++) {
                    if (data[i] > max) 
                        max = data[i];
                }
            }
        } catch (InterruptedException ie) {
            System.err.println("Oh No!");
            System.exit(-1);
        }
    }

    public static void main(String[] args) throws InterruptedException {
        int[] testData = {477, 9, 1, 177, 23};
        FindMax master = new FindMax(testData, 2);
        master.start();
        master.join();
        System.out.println(master.max);
    }
}