Renaming algorithm implementation

DummyRunnable.java

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

class DummyRunnable implements Runnable {

	public static void main(String[] args) {
		init();
		start();
	}

	private static void start() {
		for (int i = 0; i < N; i++)
			new Thread(new DummyRunnable(100 + i, i)).start();
	}

	private static void init() {
		N = 100;
		STATE = new int[N][2 * N - 1][2][N];
	}

	private static int N;
	private static int[][][][] STATE;

	private static int getState(int x, int first, int dir, int i) {
		if (dir == -1)
			dir = 0;

		return STATE[x - 1][first - 1][dir][i];
	}

	private static void setState(int x, int first, int dir, int i, int val) {
		if (dir == -1)
			dir = 0;

		STATE[x - 1][first - 1][dir][i] = val;
	}

	public DummyRunnable(int id, int i) {
		this.id = id;
		this.i = i;
	}

	private final int id, i;

	@Override
	public void run() {
		int new_id = rename(N, 1, 1);
		System.out.println(i + ": (old id, new id) = (" + id + ", " + new_id
				+ ")");
	}

	private int rename(int x, int first, int dir) {
		int last = first + dir * (2 * x - 2);
		
		System.out.println(i + ": (x, first, dir, last) = (" + x + ", " + first
				+ ", " + dir + ", " + last + ")");
		setState(x, first, dir, i, id);
		Set<Integer> competing = collectCompeting(x, first, dir);
		if (competing.size() == x) {
			
			int maxCompeting = max(competing);
			if (id == maxCompeting)
				return last;
			else
				return rename(x - 1, last - dir, -dir);
		} else {
			return rename(x - 1, first, dir);
		}
	}

	private Set<Integer> collectCompeting(int x, int first, int dir) {
		Set<Integer> collection = new HashSet<Integer>();
		for (int i = 0; i < N; i++) {
			int val = getState(x, first, dir, i);
			// Ids > 100.
			if (val > 0)
				collection.add(val);
		}

		return collection;
	}

	private static int max(Iterable<Integer> elms) {
		int max = 0;
		for (int i : elms)
			if (i > max)
				max = i;
		return max;
	}

}