UnionFindUnion.java

/*******************************************************************************
 * Copyright (c) 2012-present Jakub Kováč, Jozef Brandýs, Katarína Kotrlová,
 * Pavol Lukča, Ladislav Pápay, Viktor Tomkovič, Tatiana Tóthová
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package algvis.ds.unionfind;

import algvis.core.NodeColor;
import algvis.ui.view.REL;

public class UnionFindUnion extends UnionFindFind {
    public enum UnionHeuristic {
        NONE, BYRANK
    }

    private final UnionHeuristic unionState;
    private final UnionFind UF;
    private final UnionFindNode u;
    private final UnionFindNode v;

    public UnionFindUnion(UnionFind UF, UnionFindNode u, UnionFindNode v) {
        super(UF);
        this.UF = UF;
        this.unionState = UF.unionState;
        this.u = u;
        this.v = v;
    }

    @Override
    public void runAlgorithm() {
        setHeader("ufunion");
        u.mark();
        v.mark();
        switch (unionState) {
        case NONE:
            unionSimple(u, v);
            break;
        case BYRANK:
            unionByRank(u, v);
            break;
        default:
            break;
        }
    }

    private void unionSimple(UnionFindNode V, UnionFindNode W) {
        final UnionFindNode r1 = find(V);
        final UnionFindNode r2 = find(W);
        if (r1 == r2) {
            addStep(r1, REL.TOP, "uf-same-set");
            pause();
        } else {
            addStep(r1, REL.TOP, "ufunionsimple");
            pause();
            UF.removeFromSets(r2);
            r1.addChild(r2);
        }

        r1.unmark();
        r1.setColor(NodeColor.NORMAL);
        r2.unmark();
        r2.setColor(NodeColor.NORMAL);

        UF.reposition();
        addNote("done");
        // UF.panel.screen.V.resetView(); // only for testing, but still there
        // should
        // be some correction.
    }

    private void unionByRank(UnionFindNode V, UnionFindNode W) {
        final UnionFindNode r1 = find(V);
        final UnionFindNode r2 = find(W);
        if (r1 == r2) {
            addStep(r1, REL.TOP, "uf-same-set");
            pause();
        } else {
            addStep("ufunionbyrank", r1.getRank(), r2.getRank());
            if (r1.getRank() > r2.getRank()) {
                addStep(r1, REL.TOP, "ufunionfirstsecond");
                pause();
                UF.removeFromSets(r2);
                r1.addChild(r2);
            } else if (r1.getRank() < r2.getRank()) {
                addStep(r1, REL.TOP, "ufunionsecondfirst");
                pause();
                UF.removeFromSets(r1);
                r2.addChild(r1);
            } else {
                addStep(r1, REL.TOP, "ufunionsamerank");
                pause();
                UF.removeFromSets(r2);
                r1.addChild(r2);
                r1.setRank(r1.getRank() + 1);
            }
        }

        r1.unmark();
        r1.setColor(NodeColor.NORMAL);
        r2.unmark();
        r2.setColor(NodeColor.NORMAL);

        UF.reposition();
        addNote("done");
        // UF.panel.screen.V.resetView(); // only for testing, but still there
        // should
        // be some correction.
    }
}