feat: add console-based Tic-Tac-Toe game in puzzles and games package

src/main/java/com/thealgorithms/puzzlesandgames/TicTacToe.java

@@ -0,0 +1,85 @@
+package com.thealgorithms.puzzlesandgames;
+
+import java.util.Scanner;
+
+/**
+ * The {@code TicTacToe} class provides a console-based 2-player Tic-Tac-Toe game.
+ * Players take turns marking a 3x3 grid until one wins or the game ends in a tie.
+ *
+ * <p>
+ * This implementation demonstrates basic programming concepts in Java:
+ * 1. 2D arrays for the game board
+ * 2. Loops and conditionals for game logic
+ * 3. Input handling with {@link Scanner}
+ * </p>
+ *
+ * <p>
+ * The {@code play} method runs the game loop, {@code printBoard} displays
+ * the board, and {@code checkWin} determines if a player has won.
+ * </p>
+ *
+ * <p>
+ * Time Complexity: O(1) for each move (constant operations per turn)  
+ * Space Complexity: O(1) additional space besides the board
+ * </p>
+ */
+/**
+ * TicTacToe.java
+ * 
+ * A console-based 2-player Tic-Tac-Toe game.
+ */
+public class TicTacToe {
+    static char[][] board = {{'1','2','3'}, {'4','5','6'}, {'7','8','9'}};
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        char currentPlayer = 'X';
+        int moves = 0;
+        boolean won = false;
+
+        System.out.println("Welcome to Tic-Tac-Toe!");
+
+        while (moves < 9 && !won) {
+            printBoard();
+            System.out.print("Player " + currentPlayer + ", enter a position (1-9): ");
+            int pos = scanner.nextInt();
+            int row = (pos-1)/3;
+            int col = (pos-1)%3;
+
+            if (board[row][col] != 'X' && board[row][col] != 'O') {
+                board[row][col] = currentPlayer;
+                moves++;
+                won = checkWin(currentPlayer);
+                if (!won) currentPlayer = (currentPlayer == 'X') ? 'O' : 'X';
+            } else {
+                System.out.println("Position already taken. Try again.");
+            }
+        }
+
+        printBoard();
+        if (won) System.out.println("Player " + currentPlayer + " wins!");
+        else System.out.println("It's a tie!");
+
+        scanner.close();
+    }
+
+    static void printBoard() {
+        System.out.println();
+        for (char[] row : board) {
+            for (char c : row) System.out.print(c + " ");
+            System.out.println();
+        }
+        System.out.println();
+    }
+
+    static boolean checkWin(char player) {
+        // Rows, columns, diagonals
+        for (int i=0; i<3; i++)
+            if ((board[i][0]==player && board[i][1]==player && board[i][2]==player) ||
+                (board[0][i]==player && board[1][i]==player && board[2][i]==player))
+                return true;
+
+        return (board[0][0]==player && board[1][1]==player && board[2][2]==player) ||
+               (board[0][2]==player && board[1][1]==player && board[2][0]==player);
+    }
+}