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Find Winner on a Tic Tac Toe Game - Array - Easy - LeetCode - MiniTV

Find Winner on a Tic Tac Toe Game - Array - Easy - LeetCode - मिनी टीवी

Tic-tac-toe is played by two players A and B on a 3 x 3 grid.

Here are the rules of Tic-Tac-Toe:

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 3 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 an array moves where each element is another array of size 2 corresponding to the row and column of the grid where they mark their respective character in the order in which A and B play.

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 (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, he always plays first.

"X  "    "X  "    "X  "    "X  "    "X  "

"   " -> "   " -> " X " -> " X " -> " X "

"   "    "O  "    "O  "    "OO "    "OOX"

 

Example 2:

Input: moves = [[0,0],[1,1],[0,1],[0,2],[1,0],[2,0]]

Output: "B"

Explanation: "B" wins.

"X  "    "X  "    "XX "    "XXO"    "XXO"    "XXO"

"   " -> " O " -> " O " -> " O " -> "XO " -> "XO " 

"   "    "   "    "   "    "   "    "   "    "O  "

 

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.

"XXO"

"OOX"

"XOX"

 

Example 4:

Input: moves = [[0,0],[1,1]]

Output: "Pending"

Explanation: The game has not finished yet.

"X  "

" O "

"   "

 

Constraints:

1 <= moves.length <= 9

moves[i].length == 2

0 <= moves[i][j] <= 2

There are no repeated elements on moves.

moves follow the rules of tic tac toe.

 

Solution:

using System;
using System.Collections.Generic;
using System.Text;

namespace LeetCode.AskGif.Easy.Array
{
    public class TictactoeSoln
    {
        public string Tictactoe(int[][] moves)
        {
            var matrix = new char[3, 3];

            var playerA = true;
            var input = 'X';
            for (int i = 0; i < moves.Length; i++)
            {
                if (!playerA)
                {
                    input = 'O';                    
                }
                else
                {
                    input = 'X';
                }
                playerA = !playerA;

                //considering inputs are valid
                matrix[moves[i][0], moves[i][1]] = input;
                var check = ValidateMatrix(matrix);
                switch (check)
                {
                    case "O":
                        return "B";                        
                    case "X":
                        return "A";
                    case "Draw":
                        return "Draw";
                    case "Pending":
                        break;
                }
            }

            return "Pending";
        }

        private string ValidateMatrix(char[,] matrix)
        {
            char defaultValue = '\0';
            //First row
            if(matrix[0, 0] != defaultValue && matrix[0, 0] == matrix[0, 1] && matrix[0, 0] == matrix[0, 2])
            {
                return matrix[0, 0].ToString();
            }

            //Second row
            if (matrix[1, 0] != defaultValue &&  matrix[1, 0] == matrix[1, 1] && matrix[1, 0] == matrix[1, 2])
            {
                return matrix[1, 0].ToString();
            }

            //Third row
            if (matrix[2, 0] != defaultValue && matrix[2, 0] == matrix[2, 1] && matrix[2, 0] == matrix[2, 2])
            {
                return matrix[2, 0].ToString();
            }

            //First Column
            if (matrix[0, 0] != defaultValue && matrix[0, 0] == matrix[1, 0] && matrix[0, 0] == matrix[2, 0])
            {
                return matrix[0, 0].ToString();
            }

            //Second Column
            if (matrix[0, 1] != defaultValue && matrix[0, 1] == matrix[1, 1] && matrix[0, 1] == matrix[2, 1])
            {
                return matrix[0, 1].ToString();
            }

            //Third Column
            if (matrix[0, 2] != defaultValue && matrix[0, 2] == matrix[1, 2] && matrix[0, 2] == matrix[2, 2])
            {
                return matrix[0, 2].ToString();
            }

            //Diagonal
            if (matrix[0, 0] != defaultValue && matrix[0, 0] == matrix[1, 1] && matrix[0, 0] == matrix[2, 2])
            {
                return matrix[0, 0].ToString();
            }

            //Diagonal
            if (matrix[0, 2] != defaultValue && matrix[0, 2] == matrix[1, 1] && matrix[0, 2] == matrix[2, 0])
            {
                return matrix[0, 2].ToString();
            }

            //Check if any block is available to play
            for (int i = 0; i < 3; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    if(matrix[i,j] == defaultValue)
                    {
                        return "Pending";
                    }
                }
            }

            return "Draw";
        }
    }
}

 

Time Complexity: O(n)

Space Complexity: O(n) To Create Matrix

 

Unit Tests:

using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
    [TestClass]
    public class TictactoeSolnTests
    {
        [TestMethod]
        public void TictactoeSoln_First()
        {
            var moves = new int[,] {
                { 0, 0 },
                { 2, 0 },
                { 1, 1 },
                { 2, 1 },
                { 2, 2 }
            };

            var output = "A";
            var res = new TictactoeSoln().Tictactoe(ArrayMapper(moves));

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void TictactoeSoln_Second()
        {
            var moves = new int[,] {
                { 0, 0 },
                { 1, 1 },
                { 0, 1 },
                { 0, 2 },
                { 1, 0 },
                { 2, 0 }
            };

            var output = "B";
            var res = new TictactoeSoln().Tictactoe(ArrayMapper(moves));

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void TictactoeSoln_Third()
        {
            var moves = new int[,] {
                { 0, 0 },
                { 1, 1 },
                { 2, 0 },
                { 1, 0 },
                { 1, 2 },
                { 2, 1 },
                { 0, 1 },
                { 0, 2 },
                { 2, 2 }
            };

            var output = "Draw";
            var res = new TictactoeSoln().Tictactoe(ArrayMapper(moves));

            Assert.AreEqual(res, output);
        }

        [TestMethod]
        public void TictactoeSoln_Fourth()
        {
            var moves = new int[,] {
                { 0, 0 },
                { 1, 1 }
            };

            var output = "Pending";
            var res = new TictactoeSoln().Tictactoe(ArrayMapper(moves));

            Assert.AreEqual(res, output);
        }

        private int[][] ArrayMapper(int[,] matrix)
        {
            var arr = new int[matrix.GetLength(0)][];
            for (int i = 0; i < matrix.GetLength(0); i++)
            {
                arr[i] = new int[matrix.GetLength(1)];
                for (int j = 0; j < matrix.GetLength(1); j++)
                {
                    arr[i][j] = matrix[i, j];
                }
            }

            return arr;
        }
    }
}