Dave Medinets' Algorithm Example

Bug.java

package com.affy;

public class Bug {

    private int[] id;

    public Bug(int n) {
        id = new int[n];
        for (int i = 0; i < n; i++) {
            id[i] = i;
        }
    }

    private int root(int i) {
        while (i != id[i]) {
            i = id[i];
        }
        return i;
    }

    public boolean connected(int p, int q) {
        return root(p) == root(q);
    }

    public void WorkingUnion(int p, int q) {
        System.out.println("Union " + p + " to " + q + ": ");
        int i = root(p);
        int j = root(q);
        id[j] = i;
    }

    public void BrokenUnion(int p, int q) {
        System.out.println("Union " + p + " to " + q + ": ");
        int i = root(p);
        int j = root(q);
        System.out.println("\t2assigning " + i + " to position " + j);
        System.out.println("X: " + toString());
        id[j] = i;
        System.out.println("Y: " + toString());
    }

    public String toString() {
        StringBuffer buffer = new StringBuffer("\t");
        for (int i = 0; i < id.length; i++) {
            buffer.append(id[i]);
            buffer.append(", ");
        }
        return buffer.toString();
    }

    public static void main(String[] args) {
        Bug o = new Bug(10);
        o.WorkingUnion(5, 1);
        o.WorkingUnion(5, 7);
        o.WorkingUnion(6, 3);
        o.WorkingUnion(0, 7);
        o.WorkingUnion(9, 4);
        o.BrokenUnion(4, 6);
    }

}

/*
My output:

Union 5 to 1: 
Union 5 to 7: 
Union 6 to 3: 
Union 0 to 7: 
Union 9 to 4: 
Union 4 to 6: 
    2assigning 9 to position 6
X: 	0, 5, 2, 6, 9, 0, 6, 5, 8, 9, 
Y: 	0, 5, 2, 6, 9, 0, 9, 5, 8, 9, 

*/