Connect Four

credit for this assignment: Finn Voichick and Dennis Cosgrove

Motivation

Minimax is an important concept in game theory and search.

Negamax is a variant which relies on $\max(a,b)=-\min(-a,-b)$

While this technique is applicable to Chess (as Deep Blue employed to defeat Kasparov), we choose Connect Four as our context since it has a simpler game mechanic.

While the core part of searches like Minimax may be easy to parallelize, critical aspects such as alpha-beta pruning are more challenging.

Background

Tutorial

Solving Connect Four

Wikipedia

Minimax

Negamax

The Core Questions

• What are the tasks?
• What is the data?
• Is the data mutable?
• If so, how is it shared?

Code To Use

connectfour.core

interface Board

isDone()

getWinner()

getCurrentPlayer()

getTurnsPlayed()

createNextBoard(int column)

java.util

class Optional<T>

java.util.function

interface ToDoubleFunction<T>

interface IntPredicate

Code To Implement

Negamax

class:	ConnectFour.java
methods:	negamaxKernel selectNextColumn
package:	connectfour.studio
source folder:	student/src/main/java

method: private static double negamaxKernel(Board board, ToDoubleFunction<Board> heuristic, IntPredicate searchAtDepth, int currentDepth) (parallel implementation required)

method: public static Optional<Integer> selectNextColumn(Board board, ToDoubleFunction<Board> heuristic, IntPredicate searchAtDepth) (parallel implementation required)

Win or Lose Heuristic

class:	WinOrLoseHeuristic.java
methods:	applyAsDouble
package:	connectfour.studio
source folder:	student/src/main/java

method: public double applyAsDouble(Board board) (sequential implementation only)

Evaluate the current state of the Board. You should return a negative number if you have lost. You should return less negative numbers for losses that occur later.

OpenEndedHeuristic (Optional)

class:	OpenEndedHeuristic.java
methods:	applyAsDouble
package:	connectfour.challenge
source folder:	student/src/main/java

method: public double applyAsDouble(Board board) (sequential implementation only)

Testing Your Solution

Correctness

class:	ConnectFourTestSuite.java
package:	connnectfour.studio
source folder:	testing/src/test/java

Visualization

class:	ConnectFourViz.java	VIZ
package:	connnectfour.viz.game
source folder:	student/src//java