uni/inf2440/hw3/Parallel.java

class Parallel implements Solver {
	class Worker implements Runnable {
		MultiRadix mr;
		int[] arr;
		int start, end;
		boolean done = false;
		Worker(MultiRadix mr, int[] arr, int start, int end) {
			this.mr = mr;
			this.arr = arr;
			this.start = start;
			this.end = end;
		}

		synchronized public void run() {
			arr = mr.radixMulti(arr, start, end);
			done = true;
			notify();
		}

		synchronized public int[] getSorted() {
			while (!done) {
				try { wait(); } catch (InterruptedException ex) {}
			}
			return arr;
		}
	}

	public int[] sort(int[] arr) {
		MultiRadix mr = new MultiRadix();

		int n = 4;
		int d = arr.length / n;

		Worker[] workers = new Worker[n];
		Thread[] threads = new Thread[n];

		for (int i = 0; i < n; ++i) {
			int start = d * i;
			int end;
			if (i == n - 1)
				end = arr.length;
			else
				end = d * (i + 1);

			Worker w; Thread t;
			workers[i] = w = new Worker(mr, arr, start, end);
			threads[i] = t = new Thread(w);
			t.start();
		}

		int[][] arrs = new int[n][];
		for (int i = 0; i < n; ++i) {
			arrs[i] = workers[i].getSorted();
			try {
				threads[i].join();
			} catch (InterruptedException ex) {}
		}

		/*
		Worker w = workers[0];
		int[] a = arrs[0];
		for (int i = w.start; i < w.end; ++i) {
			System.out.print(a[i]+" ");
		}
		System.out.println("");
		System.out.println("From "+w.start+" to "+w.end);
		*/

		return arr;
	}
}