added solution for the problem snakes and ladders

Author: Vishal M Yadav

src/main/java/com/gatomalvado/snakesandladders/Main.java

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+package com.gatomalvado.snakesandladders;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Scanner;
+import java.util.Set;
+
+import com.gatomalvado.snakesandladders.model.Ladder;
+import com.gatomalvado.snakesandladders.model.Player;
+import com.gatomalvado.snakesandladders.model.Snake;
+import com.gatomalvado.snakesandladders.orchestrator.GameOrchestrator;
+
+public class Main {
+
+    public static void main(String[] args) throws InterruptedException {
+        GameOrchestrator gameOrchestrator = new GameOrchestrator(1, 1, false, 100);
+        gameOrchestrator.takeSnakeInput();
+        gameOrchestrator.takeLadderInput();
+        gameOrchestrator.takePlayerInput();
+        while(!gameOrchestrator.anyWinner()){
+            gameOrchestrator.takeTurn();
+            Thread.sleep(2000);
+        }
+    }
+}

src/main/java/com/gatomalvado/snakesandladders/README.md

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+Problem Link:- https://workat.tech/machine-coding/practice/snake-and-ladder-problem-zgtac9lxwntg
+
+Input:-
+9
+62 5
+33 6
+49 9
+88 16
+41 20
+56 53
+98 64
+93 73
+95 75
+8
+2 37
+27 46
+10 32
+51 68
+61 79
+65 84
+71 91
+81 100
+2
+Gaurav
+Sagar

src/main/java/com/gatomalvado/snakesandladders/model/Entity.java

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+package com.gatomalvado.snakesandladders.model;
+
+import com.gatomalvado.snakesandladders.model.enums.EntityType;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public class Entity {
+    protected String id;
+    protected int startPos;
+    protected int endPos;
+    protected EntityType type;
+}

src/main/java/com/gatomalvado/snakesandladders/model/Ladder.java

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+package com.gatomalvado.snakesandladders.model;
+
+import com.gatomalvado.snakesandladders.model.enums.EntityType;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+public class Ladder extends Entity {
+
+    public Ladder(String id, int xPos, int yPos) {
+        super(id, xPos, yPos, EntityType.LADDER);
+    }
+}

src/main/java/com/gatomalvado/snakesandladders/model/Player.java

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+package com.gatomalvado.snakesandladders.model;
+
+import com.gatomalvado.snakesandladders.model.enums.EntityType;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+public class Player {
+
+    private String name;
+
+    @Setter
+    private int currPos;
+
+    public Player(String name, int currPos) {
+        this.name = name;
+        this.currPos =  currPos;
+    }
+
+}

src/main/java/com/gatomalvado/snakesandladders/model/Snake.java

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+package com.gatomalvado.snakesandladders.model;
+
+import com.gatomalvado.snakesandladders.model.enums.EntityType;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+public class Snake extends Entity {
+
+    public Snake(String id, int xPos, int yPos) {
+        super(id, xPos, yPos, EntityType.SNAKE);
+    }
+}

src/main/java/com/gatomalvado/snakesandladders/model/enums/EntityType.java

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+package com.gatomalvado.snakesandladders.model.enums;
+
+import lombok.Getter;
+
+@Getter
+public enum EntityType {
+    PLAYER("player"),
+    SNAKE("snake"),
+    LADDER("ladder");
+
+    private String name;
+
+    EntityType(String name) {
+        this.name = name;
+    }
+}

src/main/java/com/gatomalvado/snakesandladders/orchestrator/GameOrchestrator.java

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+package com.gatomalvado.snakesandladders.orchestrator;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.Queue;
+
+import com.gatomalvado.snakesandladders.model.Ladder;
+import com.gatomalvado.snakesandladders.model.Player;
+import com.gatomalvado.snakesandladders.model.Snake;
+import com.gatomalvado.snakesandladders.service.BoardFactory;
+import com.gatomalvado.snakesandladders.service.BoardGenerator;
+import com.gatomalvado.snakesandladders.service.NextPositionStrategy;
+import com.gatomalvado.snakesandladders.service.WinnerDeciderStrategy;
+
+public class GameOrchestrator {
+
+    private Queue<Player> players;
+    private List<Snake> snakes;
+    private List<Ladder> ladders;
+    private final int boardLength;
+    private final NextPositionStrategy nextPositionStrategy;
+    private final WinnerDeciderStrategy winnerDeciderStrategy;
+    private final BoardGenerator boardGenerator;
+
+    public GameOrchestrator(int noOfDice, int noOfWinners, boolean autoGenerate, int boardLength) {
+        synchronized (this) {
+            BoardFactory boardFactory = new BoardFactory(noOfDice, noOfWinners, autoGenerate);
+            this.nextPositionStrategy = boardFactory.getNextPositionStrategy();
+            this.winnerDeciderStrategy = boardFactory.getWinnerDeciderStrategy();
+            this.boardGenerator = boardFactory.getBoardGenerator();
+            this.boardLength = boardLength;
+        }
+    }
+
+    public synchronized void takeSnakeInput() {
+        this.snakes = this.boardGenerator.takeSnakeInput();
+    }
+
+    public synchronized void takeLadderInput() {
+        this.ladders = this.boardGenerator.takeLadderInput();
+    }
+
+    public synchronized void takePlayerInput() {
+        this.players = this.boardGenerator.takePlayerInput();
+    }
+
+    public boolean anyWinner() {
+        return this.winnerDeciderStrategy.closeGame(this.players, this.boardLength);
+    }
+
+    public void takeTurn() {
+        Player currPlayer = players.remove();
+        this.players.add(currPlayer);
+        int rolledValue = this.nextPositionStrategy.rollDice();
+        int newPosition = currPlayer.getCurrPos() + rolledValue;
+        Optional<Snake> snake = checkForSnake(newPosition);
+        if (snake.isPresent()) {
+            int snakeFinalPos = snake.get().getEndPos();
+            System.out.println(
+                "Player " + currPlayer.getName() + " got bit by snake at " + newPosition + " and moved from " + currPlayer.getCurrPos() + " to "
+                    + snakeFinalPos);
+            currPlayer.setCurrPos(snakeFinalPos);
+            return;
+        }
+        Optional<Ladder> ladder = checkForLadder(newPosition);
+        if (ladder.isPresent()) {
+            int ladderFinalPos = ladder.get().getEndPos();
+            System.out.println(
+                "Player " + currPlayer.getName() + " got supported by a ladder at " + newPosition + " and moved from " + currPlayer.getCurrPos()
+                    + " to " + ladderFinalPos);
+            currPlayer.setCurrPos(ladderFinalPos);
+            return;
+        }
+        System.out.println("Player " + currPlayer.getName() + " moved from " + currPlayer.getCurrPos() + " to " + newPosition);
+        currPlayer.setCurrPos(newPosition);
+    }
+
+    private Optional<Snake> checkForSnake(int position) {
+        List<Snake> snakes = this.snakes.stream().filter((s) -> s.getStartPos() == position).toList();
+        if (snakes.size() == 0) {
+            return Optional.empty();
+        }
+        return Optional.of(snakes.get(0));
+    }
+
+    private Optional<Ladder> checkForLadder(int position) {
+        List<Ladder> ladders = this.ladders.stream().filter((l) -> l.getStartPos() == position).toList();
+        if (ladders.size() == 0) {
+            return Optional.empty();
+        }
+        return Optional.of(ladders.get(0));
+    }
+}

src/main/java/com/gatomalvado/snakesandladders/service/BoardFactory.java

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+package com.gatomalvado.snakesandladders.service;
+
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import lombok.Getter;
+
+@Getter
+public class BoardFactory {
+
+
+    private NextPositionStrategy nextPositionStrategy;
+
+
+    private WinnerDeciderStrategy winnerDeciderStrategy;
+
+
+    private BoardGenerator boardGenerator;
+
+    public BoardFactory(int noOfDice, int noOfWinners, boolean autoGenerate) {
+        synchronized (this) {
+            initNextPositionStrategy(noOfDice);
+            initWinnerDeciderStrategy(noOfWinners);
+            initBoardGenerator(autoGenerate);
+        }
+    }
+
+    private void initBoardGenerator(boolean autoGenerate) {
+        if(autoGenerate){
+            throw new UnsupportedOperationException("Auto generation of snakes and ladders is not supported");
+        }
+        this.boardGenerator = new ManualBoardGenerator();
+    }
+
+    private synchronized void initWinnerDeciderStrategy(int noOfWinners) {
+        switch (noOfWinners) {
+            case 1:
+                this.winnerDeciderStrategy = new SingleWinnerStrategy();
+                return;
+            default:
+                throw new UnsupportedOperationException("Only single winner is supported as of now");
+        }
+    }
+
+    private synchronized void initNextPositionStrategy(int noOfDice) {
+        switch (noOfDice) {
+            case 1:
+                this.nextPositionStrategy = new SingleDiceNextPositionStrategy();
+                return;
+            default:
+                throw new UnsupportedOperationException("Only single dice is supported as of now");
+        }
+    }
+
+}

src/main/java/com/gatomalvado/snakesandladders/service/BoardGenerator.java

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+package com.gatomalvado.snakesandladders.service;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Queue;
+import java.util.Scanner;
+import java.util.Set;
+
+import com.gatomalvado.snakesandladders.model.Ladder;
+import com.gatomalvado.snakesandladders.model.Player;
+import com.gatomalvado.snakesandladders.model.Snake;
+
+public interface BoardGenerator{
+
+    Queue<Player> takePlayerInput();
+
+    List<Snake> takeSnakeInput();
+
+    List<Ladder> takeLadderInput();
+
+}