Design Tic-Tac-Toe

Explore how to build a TicTacToe class that supports n by n gameplay. Learn to track rows, columns, and diagonals efficiently while implementing the move function that determines the winner or continuing play. Understand key concepts relevant to frequency tracking and win conditions in coding interviews.

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Statement
Examples
Understanding the problem
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Statement

Suppose that two players are playing a tic-tac-toe game on an $n \times n$ board. They’re following specific rules to play and win the game:

A move is guaranteed to be valid if a mark is placed on an empty block.
No more moves are allowed once a winning condition is reached.
A player who succeeds in placing $n$ of their marks in a horizontal, vertical, or diagonal row wins the game.

Implement a TicTacToe class, which will be used by two players to play the game and win fairly.

Keep in mind the following functionalities that need to be implemented:

Constructor, the constructor, which initializes an object of TicTacToe, allowing the players to play on a board of size $n \times n$ .
move(row, col, player) indicates that the player with the ID, player, places their mark on the cell (row, col). The move is guaranteed to be a valid move. At each move, this function returns the player ID if the current player wins and returns $0$ if no one wins.

Constraints:

$2 \leq n \leq 9$
player should be either 1 or 2.
$0 \leq$ row, col $< n$
Every call to move() will be with a unique row, col combination.
The move() function will be called at most $n^2$ times.

Examples

Design Tic-Tac-Toe

We are given the current state of a game on a $3 \times 3$ board, showing the moves made so far, where Player 1’s moves are denoted by a cross, and Player 2’s moves are denoted by a circle.

The following moves are now made by the players:

move(0, 2, 2)
move(1, 0, 1)

What would the result be?

Player 1 wins the game.

Player 2 wins the game.

No one wins the game.

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Java

usercode > TicTacToe.java

import java.util.*;
class TicTacToe {
    // Constructor will be used to initialize TicTacToe data members 
    public TicTacToe(int n) {
        // Write your code here
    }
    // move will be used to play a move by a specific player and identify who
    // wins at each move
    public int move(int row, int col, int player) {
        // Replace this placeholder return statement with your code
        return -1;
    }
}

Design Tic-Tac-Toe

Design Tic-Tac-Toe

Statement

Examples

Understanding the problem

Figure it out!

Try it yourself