Connect 4

This repository contains the source code of a connect4's (puissance 4) copy. In this game, your computer cans also play against you like a human player, good luck !

Summary

• Summary
• Credits
• Features
• Prerequisites
• Install
• Keys
• AI Functionning
  • Beginning
  • AI Update
  • Set Theory
    • Intersection
    • Union
    • Intersection implementation
  • Final AI Functionning
• Releases
• Updates

Credits

• Facon Nicolas : Creator of the project

Features

• AI plays against player

• AI cans take decisions

Prerequisites

• Windows:
  • Python
  • Git Bash
  • pygame (py -3.8 -m pip install pygame in your terminal)
• Linux: write this in terminal

  #if python is not installed yet.
  sudo apt install python3.8
  
  #if pygame is not installed yet.
  pip install pygame

Install

Once the prerequisites installed, go on your terminal (or git bash terminal) and write this:

git clone https://github.com/FACON-Nicolas/Puissance4
cd Puissance4/
#python3 or py on windows
python3 puissance-4/source/game.py

Keys

actions	keys
move right	RIGHT
move left	LEFT
place coin / Restart Game	SPACE

AI Functionning

An AI system is included in the connect 4.

But, how does this AI work ?.

beginnning

At the beginning, I wanted an AI that places its coin at the best sequences' position only. If many position are possible, then a random position is chosen.

example 1:

	0	1	2	3	4	5	6
0	-	-	-	-	-	-	-
1	-	-	-	-	-	-	-
2	-	O	X	O	X	-	-
3	O	O	X	X	O	O	-
4	O	X	X	O	O	O	X
5	X	O	O	X	X	O	X

In this situation, the AI coin is O, and the best positions to place a coin are {2, 5}, a value will be chosen randomly.

example 2:

	0	1	2	3	4	5	6
0	-	-	-	-	-	-	-
1	-	-	-	-	-	-	-
2	-	O	X	O	X	-	-
3	O	O	X	X	X	O	-
4	O	X	X	O	O	O	X
5	X	O	O	X	X	O	X

In this situation, the AI coin is O, and the best positions to place a coin are {5}, the value chosen will be 5

This algorithm gives the best positions to place an AI Coin, but there's a problem, if the human player doesn't care about the AI game, then this is almost useless, then I had to check the best next human player sequences.

AI Update

to improve my AI algorithm, I decided to check the best next human player sequences. Column by column, the human sequences will be checked and only the best position will be kept.

Example 1:

	0	1	2	3	4	5	6
0	-	-	-	-	-	-	-
1	-	-	-	-	-	-	-
2	-	O	X	O	X	-	-
3	O	O	X	X	O	O	-
4	O	X	X	O	O	O	X
5	X	O	O	X	X	O	X

In this situation, the human coin is X, and the best positions to place a human coin are {2} and the best sequences will be equal to 4, the value chosen will be 2.

Example 2:

	0	1	2	3	4	5	6
0	-	-	-	-	-	-	-
1	-	-	-	-	-	-	-
2	-	O	X	O	X	X	-
3	O	O	X	X	X	O	-
4	O	X	X	O	O	O	X
5	X	O	O	X	X	O	X

In this situation, the human coin is X, and the best positions to place a human coin are {2, 5} and the best sequences will be equal to 4, the value will be chosen randomly

Set Theory

In this AI functionning, the power of this AI is the set theory, and particularly the intersection

Intersection

The intersection's symbol is ∩.

Example:

{1, 3, 7, 9, 13} ∩ {1, 2, 6, 8, 9} = {1, 9}

Union

The intersection's symbol is ∪.

{1, 3, 7, 9, 13} ∪ {1, 2, 6, 8, 9} = {1, 2, 3, 6, 7, 8, 9, 13}

Intersection implementation

To implement an intersection, I wrote this method

def intersection(self, L1: List[int], L2: List[int]) -> List[int]:
    return [i for i in L2 if i in L1]

Final Functionning

the final functionning is:

if (sequence ai size = 4): place AI coin normally

else if (sequences human size >= 3)

.... if (intersection is not empty) place AI coin in intersection

.... else place AI coin in best human sequences

else place AI coin normally

Releases

• 1.0 : 2021-08-10
• 2.0 : 2021-10-13
• 3.0 : 2021-12-22
• 4.0 : 2022-11-10

Updates

1.0:

Create this game was my first personal challenge in development, I made it with no OOP and bad scripting.

2.0:

• OOP Development
• Linux adaptation

3.0:

• OOP Upgrade (big upgrade)
• AI upgrade (big upgrade)
• fix bugs.

4.0:

• Fix bugs

Idea of upgrades

• upgrade OOP
• add Min Max algorithm to improve the AI functionning