Use approach with minimal weight matching to determine Swiss tournament pairings

Mage.Tests/src/test/java/org/mage/test/serverside/tournament/SwissPairingMinimalWeightMatchingTest.java

@@ -0,0 +1,271 @@
+/*
+ *  Copyright 2010 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package org.mage.test.serverside.tournament;
+
+
+import java.util.*;
+
+import mage.game.tournament.*;
+import mage.game.tournament.pairing.RoundPairings;
+import mage.game.tournament.pairing.SwissPairingMinimalWeightMatching;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mage.test.stub.PlayerStub;
+import org.mage.test.stub.TournamentStub;
+
+
+/**
+ *
+ * @author Quercitron
+ */
+public class SwissPairingMinimalWeightMatchingTest {
+
+    @Test
+    public void FourPlayersSecondRoundTest() {
+        // 1 > 3
+        // 2 > 4
+
+        TournamentPlayer player1 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player2 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player3 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player4 = new TournamentPlayer(new PlayerStub(), null);
+        List<TournamentPlayer> players = new ArrayList<>();
+        players.add(player4);
+        players.add(player2);
+        players.add(player3);
+        players.add(player1);
+
+        player1.setPoints(3);
+        player2.setPoints(3);
+        player3.setPoints(0);
+        player4.setPoints(0);
+
+        List<Round> rounds = new ArrayList<>();
+        Round round = new Round(1, new TournamentStub());
+        TournamentPairing pair1 = new TournamentPairing(player1, player3);
+        round.addPairing(pair1);
+        TournamentPairing pair2 = new TournamentPairing(player4, player2);
+        round.addPairing(pair2);
+        rounds.add(round);
+
+        SwissPairingMinimalWeightMatching swissPairing = new SwissPairingMinimalWeightMatching(players, rounds);
+        RoundPairings roundPairings = swissPairing.getRoundPairings();
+
+        Assert.assertEquals(2, roundPairings.getPairings().size());
+        Assert.assertEquals(0, roundPairings.getPlayerByes().size());
+
+        CheckPair(roundPairings.getPairings(), player1, player2);
+        CheckPair(roundPairings.getPairings(), player3, player4);
+    }
+
+    @Test
+    public void FourPlayersSecondThirdTest() {
+        // 1 > 3
+        // 2 > 4
+        //
+        // 1 > 2
+        // 3 > 4
+
+        TournamentPlayer player3 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player2 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player4 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player1 = new TournamentPlayer(new PlayerStub(), null);
+        List<TournamentPlayer> players = new ArrayList<>();
+        players.add(player4);
+        players.add(player2);
+        players.add(player3);
+        players.add(player1);
+
+        player1.setPoints(6);
+        player2.setPoints(3);
+        player3.setPoints(3);
+        player4.setPoints(0);
+
+        List<Round> rounds = new ArrayList<>();
+        // round 1
+        Round round = new Round(1, new TournamentStub());
+        TournamentPairing pair1 = new TournamentPairing(player1, player3);
+        round.addPairing(pair1);
+        TournamentPairing pair2 = new TournamentPairing(player4, player2);
+        round.addPairing(pair2);
+        rounds.add(round);
+        // round 2
+        round = new Round(2, new TournamentStub());
+        pair1 = new TournamentPairing(player2, player1);
+        round.addPairing(pair1);
+        pair2 = new TournamentPairing(player4, player3);
+        round.addPairing(pair2);
+        rounds.add(round);
+
+        SwissPairingMinimalWeightMatching swissPairing = new SwissPairingMinimalWeightMatching(players, rounds);
+        RoundPairings roundPairings = swissPairing.getRoundPairings();
+
+        Assert.assertEquals(2, roundPairings.getPairings().size());
+        Assert.assertEquals(0, roundPairings.getPlayerByes().size());
+
+        CheckPair(roundPairings.getPairings(), player1, player4);
+        CheckPair(roundPairings.getPairings(), player2, player3);
+    }
+
+    @Test
+    public void FivePlayersThirdRoundTest() {
+        // 1 > 2
+        // 3 > 4
+        // 5
+        //
+        // 1 > 5
+        // 2 > 3
+        // 4
+
+        TournamentPlayer player1 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player2 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player3 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player4 = new TournamentPlayer(new PlayerStub(), null);
+        TournamentPlayer player5 = new TournamentPlayer(new PlayerStub(), null);
+        List<TournamentPlayer> players = new ArrayList<>();
+        players.add(player4);
+        players.add(player2);
+        players.add(player5);
+        players.add(player3);
+        players.add(player1);
+
+        player1.setPoints(6);
+        player2.setPoints(3);
+        player3.setPoints(3);
+        player4.setPoints(3);
+        player5.setPoints(3);
+
+        List<Round> rounds = new ArrayList<>();
+        // first round
+        Round round = new Round(1, new TournamentStub());
+        TournamentPairing pair1 = new TournamentPairing(player1, player2);
+        round.addPairing(pair1);
+        TournamentPairing pair2 = new TournamentPairing(player3, player4);
+        round.addPairing(pair2);
+        round.getPlayerByes().add(player5);
+        rounds.add(round);
+        // second round
+        round = new Round(1, new TournamentStub());
+        pair1 = new TournamentPairing(player1, player5);
+        round.addPairing(pair1);
+        pair2 = new TournamentPairing(player2, player3);
+        round.addPairing(pair2);
+        round.getPlayerByes().add(player4);
+        rounds.add(round);
+
+        SwissPairingMinimalWeightMatching swissPairing = new SwissPairingMinimalWeightMatching(players, rounds);
+        RoundPairings roundPairings = swissPairing.getRoundPairings();
+
+        Assert.assertEquals(2, roundPairings.getPairings().size());
+        Assert.assertEquals(1, roundPairings.getPlayerByes().size());
+
+        CheckPair(roundPairings.getPairings(), player1, player4);
+        CheckPair(roundPairings.getPairings(), player2, player5);
+        Assert.assertTrue(roundPairings.getPlayerByes().contains(player3));
+    }
+
+    @Test
+    public void SimulateDifferentTournaments() {
+        int playersCount = 12;
+        for (int i = 0; i <= playersCount; i++) {
+            int roundsCount = ((i + 1) / 2) * 2 - 1;
+            for (int j = 1; j <= roundsCount; j++) {
+                SimulateTournament(i, j);
+            }
+        }
+    }
+
+    private void SimulateTournament(int playersCount, int roundsCount) {
+        Random rnd = new Random();
+
+        List<TournamentPlayer> players = new ArrayList<>();
+        for (int i = 0; i < playersCount; i++) {
+            players.add(new TournamentPlayer(new PlayerStub(), null));
+        }
+
+        List<TournamentPairing> playedPairs = new ArrayList<>();
+        Set<TournamentPlayer> playersByes = new HashSet<>();
+
+        List<Round> rounds = new ArrayList<>();
+        for (int i = 0; i < roundsCount; i++) {
+            SwissPairingMinimalWeightMatching swissPairing = new SwissPairingMinimalWeightMatching(new ArrayList<>(players), rounds);
+            RoundPairings roundPairings = swissPairing.getRoundPairings();
+
+            Assert.assertEquals(playersCount / 2, roundPairings.getPairings().size());
+            Assert.assertEquals(playersCount % 2, roundPairings.getPlayerByes().size());
+
+            Round round = new Round(1, new TournamentStub());
+            rounds.add(round);
+            for (TournamentPairing pairing : roundPairings.getPairings()) {
+                if (ContainsPair(playedPairs, pairing.getPlayer1(), pairing.getPlayer2())) {
+                    if (i < (playersCount + 1) / 2) {
+                        throw new AssertionError("Match between players has been played already.");
+                    }
+                }
+                playedPairs.add(pairing);
+
+                round.addPairing(pairing);
+                if (rnd.nextBoolean()) {
+                    pairing.getPlayer1().setPoints(pairing.getPlayer1().getPoints() + 3);
+                } else {
+                    pairing.getPlayer2().setPoints(pairing.getPlayer2().getPoints() + 3);
+                }
+            }
+            for (TournamentPlayer playerBye : roundPairings.getPlayerByes()) {
+                if (playersByes.contains(playerBye)) {
+                    throw new AssertionError("Player already had bye.");
+                }
+                playersByes.add(playerBye);
+
+                round.getPlayerByes().add(playerBye);
+                playerBye.setPoints(playerBye.getPoints() + 3);
+            }
+        }
+    }
+
+    private void CheckPair(List<TournamentPairing> pairs, TournamentPlayer player1, TournamentPlayer player2) {
+        if (!ContainsPair(pairs, player1, player2)) {
+            throw new AssertionError("Pairing doesn't contain expected pair of players.");
+        }
+    }
+
+    private boolean ContainsPair(List<TournamentPairing> pairs, TournamentPlayer player1, TournamentPlayer player2) {
+        for (TournamentPairing pair : pairs) {
+            if (pair.getPlayer1().equals(player1) && pair.getPlayer2().equals(player2)) {
+                return true;
+            }
+            if (pair.getPlayer1().equals(player2) && pair.getPlayer2().equals(player1)) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
+

Mage.Tests/src/test/java/org/mage/test/stub/TournamentStub.java

@@ -0,0 +1,237 @@
+/*
+ *  Copyright 2010 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package org.mage.test.stub;
+
+import mage.cards.ExpansionSet;
+import mage.cards.decks.Deck;
+import mage.game.draft.Draft;
+import mage.game.events.Listener;
+import mage.game.events.PlayerQueryEvent;
+import mage.game.events.TableEvent;
+import mage.game.tournament.*;
+import mage.players.Player;
+
+import java.util.Collection;
+import java.util.Date;
+import java.util.List;
+import java.util.UUID;
+
+/**
+ *
+ * @author Quercitron
+ */
+public class TournamentStub implements Tournament {
+
+    private final UUID id = UUID.randomUUID();
+
+    @Override
+    public UUID getId() {
+        return id;
+    }
+
+    @Override
+    public void addPlayer(Player player, String playerType) {
+
+    }
+
+    @Override
+    public void removePlayer(UUID playerId) {
+
+    }
+
+    @Override
+    public TournamentPlayer getPlayer(UUID playerId) {
+        return null;
+    }
+
+    @Override
+    public Collection<TournamentPlayer> getPlayers() {
+        return null;
+    }
+
+    @Override
+    public Collection<Round> getRounds() {
+        return null;
+    }
+
+    @Override
+    public List<ExpansionSet> getSets() {
+        return null;
+    }
+
+    @Override
+    public void updateResults() {
+
+    }
+
+    @Override
+    public void setBoosterInfo(String setInfo) {
+
+    }
+
+    @Override
+    public String getBoosterInfo() {
+        return null;
+    }
+
+    @Override
+    public void submitDeck(UUID playerId, Deck deck) {
+
+    }
+
+    @Override
+    public void updateDeck(UUID playerId, Deck deck) {
+
+    }
+
+    @Override
+    public void autoSubmit(UUID playerId, Deck deck) {
+
+    }
+
+    @Override
+    public boolean allJoined() {
+        return false;
+    }
+
+    @Override
+    public boolean isDoneConstructing() {
+        return false;
+    }
+
+    @Override
+    public void quit(UUID playerId) {
+
+    }
+
+    @Override
+    public void leave(UUID playerId) {
+
+    }
+
+    @Override
+    public void nextStep() {
+
+    }
+
+    @Override
+    public void addTableEventListener(Listener<TableEvent> listener) {
+
+    }
+
+    @Override
+    public void addPlayerQueryEventListener(Listener<PlayerQueryEvent> listener) {
+
+    }
+
+    @Override
+    public void fireConstructEvent(UUID playerId) {
+
+    }
+
+    @Override
+    public TournamentOptions getOptions() {
+        return null;
+    }
+
+    @Override
+    public void setStartTime() {
+
+    }
+
+    @Override
+    public Date getStartTime() {
+        return null;
+    }
+
+    @Override
+    public Date getEndTime() {
+        return null;
+    }
+
+    @Override
+    public Date getStepStartTime() {
+        return null;
+    }
+
+    @Override
+    public void setStepStartTime(Date date) {
+
+    }
+
+    @Override
+    public TournamentType getTournamentType() {
+        return null;
+    }
+
+    @Override
+    public void setTournamentType(TournamentType tournamentType) {
+
+    }
+
+    @Override
+    public String getTournamentState() {
+        return null;
+    }
+
+    @Override
+    public void setTournamentState(String tournamentState) {
+
+    }
+
+    @Override
+    public int getNumberRounds() {
+        return 0;
+    }
+
+    @Override
+    public void cleanUpOnTournamentEnd() {
+
+    }
+
+    @Override
+    public boolean isAbort() {
+        return false;
+    }
+
+    @Override
+    public void setAbort(boolean abort) {
+
+    }
+
+    @Override
+    public void clearDraft() {
+
+    }
+
+    @Override
+    public Draft getDraft() {
+        return null;
+    }
+}

Mage/src/mage/game/tournament/TournamentSwiss.java

@@ -27,13 +27,15 @@
  */
 package mage.game.tournament;
 
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
+
 import mage.constants.TournamentPlayerState;
 import mage.game.events.TableEvent;
+import mage.game.tournament.pairing.RoundPairings;
+import mage.game.tournament.pairing.SwissPairingMinimalWeightMatching;
+import mage.game.tournament.pairing.SwissPairingSimple;
 
 /**
  *
@@ -65,76 +67,35 @@ public abstract class TournamentSwiss extends TournamentImpl {
     }
 
     protected Round createRoundSwiss() {
+        List<TournamentPlayer> roundPlayers = getActivePlayers();
+
+        RoundPairings roundPairings;
+        if (roundPlayers.size() <= 16) {
+            SwissPairingMinimalWeightMatching swissPairing = new SwissPairingMinimalWeightMatching(roundPlayers, rounds);
+            roundPairings = swissPairing.getRoundPairings();
+        } else {
+            SwissPairingSimple swissPairing = new SwissPairingSimple(roundPlayers, rounds);
+            roundPairings = swissPairing.getRoundPairings();
+        }
+
         Round round = new Round(rounds.size() + 1, this);
         rounds.add(round);
-        List<TournamentPlayer> roundPlayers = getActivePlayers();
-        // sort players by tournament points
-        Collections.sort(roundPlayers, new Comparator<TournamentPlayer>() {
-            @Override
-            public int compare(TournamentPlayer p1, TournamentPlayer p2) {
-                return p2.getPoints() - p1.getPoints();
-            }
-
-        });
-        // create pairings
-        while (roundPlayers.size() > 0) {
-            TournamentPlayer player1 = roundPlayers.get(0);
-            roundPlayers.remove(0);
-            TournamentPlayer playerForPossibleSecondPairing = null;
-            for (TournamentPlayer player2 : roundPlayers) {
-                if (alreadyPaired(player1, player2)) {
-                    // if already paired but equal points -> remember if second pairing is needed
-                    if (playerForPossibleSecondPairing == null) {
-                        playerForPossibleSecondPairing = player2;
-                    }
-                } else {
-                    if (player2.getPoints() < player1.getPoints() && playerForPossibleSecondPairing != null) {
-                        // pair again with a player
-                        round.addPairing(new TournamentPairing(player1, playerForPossibleSecondPairing));
-                        roundPlayers.remove(playerForPossibleSecondPairing);
-                        player1 = null;
-                        break;
-                    } else {
-                        // pair agains the next not paired before
-                        round.addPairing(new TournamentPairing(player1, player2));
-                        roundPlayers.remove(player2);
-                        player1 = null;
-                        break;
-                    }
-                }
-            }
-            if (player1 != null) {
-                // no pairing done yet
-                if (playerForPossibleSecondPairing != null) {
-                    // pair again with a player
-                    round.addPairing(new TournamentPairing(player1, playerForPossibleSecondPairing));
-                    roundPlayers.remove(playerForPossibleSecondPairing);
-                } else {
-                    // player free round - add to bye players of this round
-                    round.getPlayerByes().add(player1);
-                    if (round.getRoundNumber() == getNumberRounds()) {
-                        player1.setState(TournamentPlayerState.FINISHED);
-                    } else {
-                        player1.setState(TournamentPlayerState.WAITING);
-                    }
-                    player1.setStateInfo("Round Bye");
-                    updateResults();
-                }
-            }
+        for (TournamentPairing pairing : roundPairings.getPairings()) {
+            round.addPairing(pairing);
         }
+        for (TournamentPlayer playerBye : roundPairings.getPlayerByes()) {
+            // player free round - add to bye players of this round
+            round.getPlayerByes().add(playerBye);
+            if (round.getRoundNumber() == getNumberRounds()) {
+                playerBye.setState(TournamentPlayerState.FINISHED);
+            } else {
+                playerBye.setState(TournamentPlayerState.WAITING);
+            }
+            playerBye.setStateInfo("Round Bye");
+            updateResults();
+        }
+
         return round;
     }
 
-    protected boolean alreadyPaired(TournamentPlayer player1, TournamentPlayer player2) {
-        for (Round round : rounds) {
-            for (TournamentPairing pairing : round.getPairs()) {
-                if (pairing.getPlayer1().equals(player1) || pairing.getPlayer2().equals(player1)) {
-                    if (pairing.getPlayer1().equals(player2) || pairing.getPlayer2().equals(player2)) {
-                        return true;
-                    }
-                }
-            }
-        }
-        return false;
-    }
 }

Mage/src/mage/game/tournament/pairing/RoundPairings.java

@@ -0,0 +1,64 @@
+/*
+ *  Copyright 2011 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package mage.game.tournament.pairing;
+
+import mage.game.tournament.TournamentPairing;
+import mage.game.tournament.TournamentPlayer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *
+ * @author Quercitron
+ */
+public class RoundPairings {
+
+    public RoundPairings() {
+        this(new ArrayList<TournamentPairing>(), new ArrayList<TournamentPlayer>());
+    }
+
+    public RoundPairings(List<TournamentPairing> pairings, List<TournamentPlayer> playerByes) {
+        this.pairings = pairings;
+        this.playerByes = playerByes;
+    }
+
+    private final List<TournamentPairing> pairings;
+
+    private final List<TournamentPlayer> playerByes;
+
+    public List<TournamentPairing> getPairings() {
+        return pairings;
+    }
+
+    public List<TournamentPlayer> getPlayerByes() {
+        return playerByes;
+    }
+
+}

Mage/src/mage/game/tournament/pairing/SwissPairingMinimalWeightMatching.java

@@ -0,0 +1,283 @@
+/*
+ *  Copyright 2011 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package mage.game.tournament.pairing;
+
+import mage.game.tournament.Round;
+import mage.game.tournament.TournamentPairing;
+import mage.game.tournament.TournamentPlayer;
+
+import java.util.*;
+
+/**
+ *
+ * @author Quercitron
+ */
+
+// SwissPairingMinimalWeightMatching creates round pairings for swiss tournament.
+// It assigns weight to each possible pair and searches perfect matching with minimal weight
+// for more details see https://www.leaguevine.com/blog/18/swiss-tournament-scheduling-leaguevines-new-algorithm/
+// This implementation don't use fast minimum weight maximum matching algorithm,
+// it uses brute-force search, so it works reasonably fast only up to 16 players.
+
+public class SwissPairingMinimalWeightMatching {
+
+    private final int playersCount;
+
+    List<PlayerInfo> swissPlayers;
+
+    // number of vertexes in graph
+    private final int n;
+
+    // weight of pairings
+    private final int[][] w;
+
+    public SwissPairingMinimalWeightMatching(List<TournamentPlayer> players, List<Round> rounds) {
+        playersCount = players.size();
+
+        swissPlayers = new ArrayList<PlayerInfo>();
+        for (int i = 0; i < playersCount; i++) {
+            PlayerInfo swissPlayer = new PlayerInfo();
+            swissPlayer.tournamentPlayer = players.get(i);
+            swissPlayer.playerId = players.get(i).getPlayer().getId();
+            swissPlayer.points = players.get(i).getPoints();
+            swissPlayers.add(swissPlayer);
+        }
+
+        // shuffle players first to add some randomness
+        Collections.shuffle(swissPlayers);
+        Map<UUID, Integer> map = new HashMap<>();
+        for (int i = 0; i < playersCount; i++) {
+            swissPlayers.get(i).id = i;
+            map.put(swissPlayers.get(i).playerId, i);
+        }
+
+        // calculate Tie Breaker points -- Sum of Opponents' Scores (SOS)
+        // see http://senseis.xmp.net/?SOS
+        for (Round round : rounds) {
+            for (TournamentPairing pairing : round.getPairs()) {
+                TournamentPlayer player1 = pairing.getPlayer1();
+                TournamentPlayer player2 = pairing.getPlayer2();
+
+                int id1 = map.get(player1.getPlayer().getId());
+                int id2 = map.get(player2.getPlayer().getId());
+
+                swissPlayers.get(id1).sosPoints += player2.getPoints();
+                swissPlayers.get(id2).sosPoints += player1.getPoints();
+                // todo: sos points for byes? maybe add player points?
+            }
+        }
+
+        // sort by points and then by sos points
+        Collections.sort(swissPlayers, new Comparator<PlayerInfo>() {
+            @Override
+            public int compare(PlayerInfo p1, PlayerInfo p2) {
+                int result = p2.points - p1.points;
+                if (result != 0) {
+                    return result;
+                }
+                return p2.sosPoints - p1.sosPoints;
+            }
+        });
+
+        // order could be changed, update ids and mapping
+        for (int i = 0; i < playersCount; i++) {
+            swissPlayers.get(i).id = i;
+            map.put(swissPlayers.get(i).playerId, i);
+        }
+
+        // count ties and matches between players
+        int[][] duels = new int[playersCount][playersCount];
+        int[] byes = new int[playersCount];
+        for (Round round : rounds) {
+            for (TournamentPairing pairing : round.getPairs()) {
+                TournamentPlayer player1 = pairing.getPlayer1();
+                TournamentPlayer player2 = pairing.getPlayer2();
+
+                int id1 = map.get(player1.getPlayer().getId());
+                int id2 = map.get(player2.getPlayer().getId());
+
+                duels[id1][id2]++;
+                duels[id2][id1]++;
+            }
+            for (TournamentPlayer playerBye : round.getPlayerByes()) {
+                int id = map.get(playerBye.getPlayer().getId());
+                byes[id]++;
+            }
+        }
+
+        // set vertex count
+        // add vertex for bye if we have odd number of players
+        n = (playersCount % 2 == 1 ? playersCount + 1 : playersCount);
+
+        // calculate weight
+        // try to pair players with equal scores
+        w = new int[n][n];
+        for (int i = 0; i < playersCount; i++) {
+            PlayerInfo player = swissPlayers.get(i);
+            for (int p = player.points; p >= 0 ; p--) {
+                int first = -1;
+                int last = -1;
+                for (int j = 0; j < playersCount; j++) {
+                    if (swissPlayers.get(j).points == p) {
+                        if (first < 0) {
+                            first = j;
+                        }
+                        last = j;
+                    }
+                }
+                if (first < 0) {
+                    continue;
+                }
+                int self = (p == player.points ? i : first - 1);
+                int diff = 10 * (player.points - p);
+                for (int j = Math.max(first, i); j <= last; j++) {
+                    w[i][j] = Math.abs(j - (last + first - self)) + diff;
+                    w[j][i] = w[i][j];
+                }
+            }
+        }
+
+        // avoid pairing players that have played each other already
+        for (int i = 0; i < playersCount; i++) {
+            for (int j = 0; j < i; j++) {
+                w[i][j] += duels[i][j] * 500;
+                w[j][i] = w[i][j];
+            }
+        }
+
+        // try to give bye to a player with a low score
+        // try to avoid giving the same person multiple byes
+        if (n > playersCount) {
+            for (int i = 0; i < playersCount; i++) {
+                w[i][n - 1] = 10 * (swissPlayers.get(i).points - swissPlayers.get(playersCount - 1).points) + (playersCount - i - 1);
+                w[i][n - 1] += byes[i] * 2000;
+                w[n - 1][i] = w[i][n - 1];
+            }
+        }
+
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < n; j++) {
+                w[i][j] *= w[i][j];
+            }
+        }
+
+        // initialize variables for backtrack
+        used = new boolean[n];
+        pairs = new int[n];
+        Arrays.fill(pairs, -1);
+        result = new int[n];
+        weight = 0;
+        minCost = -1;
+        makePairings(0);
+    }
+
+    public RoundPairings getRoundPairings() {
+        // return round pairings with minimal weight
+        List<TournamentPairing> pairings = new ArrayList<>();
+        List<TournamentPlayer> playerByes = new ArrayList<>();
+
+        Map<Integer, TournamentPlayer> map  = new HashMap<>();
+        for (PlayerInfo player : swissPlayers) {
+            map.put(player.id, player.tournamentPlayer);
+        }
+
+        if (n > playersCount) {
+            // last vertex -- bye
+            playerByes.add(map.get(result[n - 1]));
+            result[result[n - 1]] = -1;
+            result[n - 1] = -1;
+        }
+
+        for (int i = 0; i < playersCount; i++) {
+            if (result[i] >= 0) {
+                pairings.add(new TournamentPairing(map.get(i), map.get(result[i])));
+                result[result[i]] = -1;
+                result[i] = -1;
+            }
+        }
+
+        return new RoundPairings(pairings, playerByes);
+    }
+
+    boolean[] used;
+
+    // current pairs
+    int[] pairs;
+    // current weight
+    int weight;
+
+    int[] result;
+    int minCost;
+
+    // backtrack all possible pairings and choose one with minimal weight
+    private void makePairings(int t) {
+        if (t >= n) {
+            if (minCost < 0 || minCost > weight) {
+                minCost = weight;
+                System.arraycopy(pairs, 0, result, 0, n);
+            }
+            return;
+        }
+
+        if (!used[t]) {
+            for (int i = t + 1; i < n; i++) {
+                if (!used[i]) {
+                    pairs[t] = i;
+                    pairs[i] = t;
+                    used[t] = true;
+                    used[i] = true;
+                    weight += w[t][i];
+
+                    makePairings(t + 1);
+
+                    pairs[t] = -1;
+                    pairs[i] = -1;
+                    used[t] = false;
+                    used[i] = false;
+                    weight -= w[t][i];
+                }
+            }
+        } else {
+            makePairings(t + 1);
+        }
+    }
+
+    class PlayerInfo {
+        public int id;
+
+        public TournamentPlayer tournamentPlayer;
+
+        public UUID playerId;
+
+        public int points;
+
+        public int sosPoints;
+    }
+}
+

Mage/src/mage/game/tournament/pairing/SwissPairingSimple.java

@@ -0,0 +1,124 @@
+/*
+ *  Copyright 2011 BetaSteward_at_googlemail.com. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without modification, are
+ *  permitted provided that the following conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above copyright notice, this list of
+ *        conditions and the following disclaimer.
+ *
+ *     2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *        of conditions and the following disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY BetaSteward_at_googlemail.com ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ *  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BetaSteward_at_googlemail.com OR
+ *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  The views and conclusions contained in the software and documentation are those of the
+ *  authors and should not be interpreted as representing official policies, either expressed
+ *  or implied, of BetaSteward_at_googlemail.com.
+ */
+
+package mage.game.tournament.pairing;
+
+import mage.game.tournament.Round;
+import mage.game.tournament.TournamentPairing;
+import mage.game.tournament.TournamentPlayer;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ *
+ * @author BetaSteward_at_googlemail.com
+ * @author Quercitron
+ */
+public class SwissPairingSimple {
+
+    private final RoundPairings roundPairings;
+
+    public SwissPairingSimple(List<TournamentPlayer> players, List<Round> rounds) {
+        roundPairings = getPairingsSimple(players, rounds);
+    }
+
+    public RoundPairings getRoundPairings() {
+        return roundPairings;
+    }
+
+    private RoundPairings getPairingsSimple(List<TournamentPlayer> players, List<Round> rounds) {
+        List<TournamentPairing> pairings = new ArrayList<>();
+        List<TournamentPlayer> playerByes = new ArrayList<>();
+
+        // sort players by tournament points
+        Collections.sort(players, new Comparator<TournamentPlayer>() {
+            @Override
+            public int compare(TournamentPlayer p1, TournamentPlayer p2) {
+                return p2.getPoints() - p1.getPoints();
+            }
+
+        });
+        // create pairings
+        while (players.size() > 0) {
+            TournamentPlayer player1 = players.get(0);
+            players.remove(0);
+            TournamentPlayer playerForPossibleSecondPairing = null;
+            for (TournamentPlayer player2 : players) {
+                if (alreadyPaired(rounds, player1, player2)) {
+                    // if already paired but equal points -> remember if second pairing is needed
+                    if (playerForPossibleSecondPairing == null) {
+                        playerForPossibleSecondPairing = player2;
+                    }
+                } else {
+                    if (player2.getPoints() < player1.getPoints() && playerForPossibleSecondPairing != null) {
+                        // pair again with a player
+                        pairings.add(new TournamentPairing(player1, playerForPossibleSecondPairing));
+                        players.remove(playerForPossibleSecondPairing);
+                        player1 = null;
+                        break;
+                    } else {
+                        // pair agains the next not paired before
+                        pairings.add(new TournamentPairing(player1, player2));
+                        players.remove(player2);
+                        player1 = null;
+                        break;
+                    }
+                }
+            }
+            if (player1 != null) {
+                // no pairing done yet
+                if (playerForPossibleSecondPairing != null) {
+                    // pair again with a player
+                    pairings.add(new TournamentPairing(player1, playerForPossibleSecondPairing));
+                    players.remove(playerForPossibleSecondPairing);
+                } else {
+                    // player free round - add to bye players of this round
+                    playerByes.add(player1);
+                }
+            }
+        }
+
+        return new RoundPairings(pairings, playerByes);
+    }
+
+    private boolean alreadyPaired(List<Round> rounds, TournamentPlayer player1, TournamentPlayer player2) {
+        for (Round round : rounds) {
+            for (TournamentPairing pairing : round.getPairs()) {
+                if (pairing.getPlayer1().equals(player1) || pairing.getPlayer2().equals(player1)) {
+                    if (pairing.getPlayer1().equals(player2) || pairing.getPlayer2().equals(player2)) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+}