Find the Winner of a Tic Tac Toe Game

Easy
3
19.7% Acceptance

In this lab, you will be implementing a function to determine the winner of a tic-tac-toe game. Tic-tac-toe is a popular two-player game played on a 3 x 3 grid. The players, A and B, take turns placing characters, 'X' and 'O' respectively, into empty squares on the grid. The game ends when there are three of the same (non-empty) character filling any row, column, or diagonal, or if all squares are non-empty and no moves can be played.

You are given a 2D integer array moves where moves[i] = [rowi, coli] indicates that the ith move will be played on grid[rowi][coli]. Your task is to implement a function tictactoe(moves) that returns the winner of the game if it exists (A or B). If the game ends in a draw, return "Draw" and if there are still moves to be played, return "Pending".

You can assume that moves is valid, following the rules of tic-tac-toe, the grid is initially empty, and A will play first.

Example 1:

const moves = [[0,0],[2,0],[1,1],[2,1],[2,2]]; console.log(tictactoe(moves)); // Output: "A"

In this example, player A wins the game as they always play first.

Example 2:

const moves = [[0,0],[1,1],[0,1],[0,2],[1,0],[2,0]]; console.log(tictactoe(moves)); // Output: "B"

In this example, player B wins the game.

Example 3:

const moves = [[0,0],[1,1],[2,0],[1,0],[1,2],[2,1],[0,1],[0,2],[2,2]]; console.log(tictactoe(moves)); // Output: "Draw"

In this example, the game ends in a draw since there are no moves to make.

Constraints:

  • 1 <= moves.length <= 9
  • moves[i].length == 2
  • 0 <= rowi, coli <= 2
  • There are no repeated elements on moves.
  • moves follows the rules of tic-tac-toe.

Write the function tictactoe in the provided index.js file.

Challenges

  1. Export your function as tictactoe from your file.
  2. Your function tictactoe should return a string, which is the winner of the game.
  3. The function should handle invalid or empty inputs and return a string "Invalid moves".