Game Design• Patterns: Singleton

Tic Tac Toe

Easy

Problem Summary

Design a modular Tic Tac Toe game supporting two players on an N x N board with dynamic win-checking.

Functional Scope

Support customizable board sizes (default 3x3).
Alternating turn sequence for Player X and Player O.
Check win condition in O(1) time after each move.
Detect draw states when all cells are filled without a winner.

Entity-Relationship (ER) Schema

GameEngine [1] <---> [1] Board
GameEngine [1] <---> [2] Player
Board [1] <---> [N*N] Cell
Cell [1] <---> [1] Symbol

Design Approach

To check wins in O(1) time, keep rows and cols count arrays for each player symbol, along with main and anti-diagonal counters.

Core Classes & Models

Board (Holds grid cells)Player (Symbol: X or O, Name)GameEngine (Runs turn iterations and checks states)

Code Blueprint

public enum Symbol { X, O, EMPTY }

public class Board {
    private Symbol[][] grid;
    private int size;
    public Board(int size) {
        this.size = size;
        grid = new Symbol[size][size];
    }
    public boolean makeMove(int r, int c, Symbol s) {
        if (grid[r][c] != Symbol.EMPTY) return false;
        grid[r][c] = s;
        return true;
    }
}