Introduction

In this blog post, we will explore how to solve the LeetCode problem "1275" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Tic-tac-toe is played by two players A and B on a 3 x 3 grid. The rules of Tic-Tac-Toe are: Players take turns placing characters into empty squares ' '. The first player A always places 'X' characters, while the second player B always places 'O' characters. 'X' and 'O' characters are always placed into empty squares, never on filled ones. The game ends when there are three of the same (non-empty) character filling any row, column, or diagonal. The game also ends if all squares are non-empty. No more moves can be played if the game is over. Given a 2D integer array moves where moves[i] = [rowi, coli] indicates that the ith move will be played on grid[rowi][coli]. return the winner of the game if it exists (A or B). In case the game ends in a draw return "Draw". If there are still movements to play return "Pending". You can assume that moves is valid (i.e., it follows the rules of Tic-Tac-Toe), the grid is initially empty, and A will play first. Example 1: Input: moves = [[0,0],[2,0],[1,1],[2,1],[2,2]] Output: "A" Explanation: A wins, they always play first. Example 2: Input: moves = [[0,0],[1,1],[0,1],[0,2],[1,0],[2,0]] Output: "B" Explanation: B wins. Example 3: Input: moves = [[0,0],[1,1],[2,0],[1,0],[1,2],[2,1],[0,1],[0,2],[2,2]] Output: "Draw" Explanation: 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 follow the rules of tic tac toe.

Explanation

• Simulate the Tic-Tac-Toe game based on the given moves.
  • After each move, check if the current player has won.
  • If no winner is found after all moves, determine if the game is a draw or pending.

• Runtime Complexity: O(N), where N is the number of moves. Storage Complexity: O(1).

Code

    def ti_ta_toe(moves):    """
    Determines the winner of a Tic-Tac-Toe game given a list of moves.

    Args:
        moves: A list of moves, where each move is a list [row, col].

    Returns:
        "A" if player A wins, "B" if player B wins, "Draw" if the game ends in a draw,
        or "Pending" if there are still moves to play.
    """

    board = [['' for _ in range(3)] for _ in range(3)]
    player = 'X'

    for move in moves:
        row, col = move
        board[row][col] = player

        # Check for a win
        if check_win(board, player):
            return "A" if player == 'X' else "B"

        player = 'O' if player == 'X' else 'X'

    # Check for a draw
    if len(moves) == 9:
        return "Draw"
    else:
        return "Pending"


def check_win(board, player):
    """
    Checks if the given player has won the Tic-Tac-Toe game.

    Args:
        board: The current state of the board.
        player: The player to check for a win.

    Returns:
        True if the player has won, False otherwise.
    """

    # Check rows
    for row in range(3):
        if board[row][0] == player and board[row][1] == player and board[row][2] == player:
            return True

    # Check columns
    for col in range(3):
        if board[0][col] == player and board[1][col] == player and board[2][col] == player:
            return True

    # Check diagonals
    if board[0][0] == player and board[1][1] == player and board[2][2] == player:
        return True
    if board[0][2] == player and board[1][1] == player and board[2][0] == player:
        return True

    return False