1275. Find Winner on a Tic Tac Toe Game

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 "    "OO

X

"

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"    "XX

O

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

O

 " 
"   "    "   "    "   "    "   "    "   "    "

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.
class Solution {
    public String tictactoe(int[][] moves) {
        
        
        for (int a = 0; a <= 1; a++ ){
            int[] x = new int[3];
            int[] y = new int[3];
            int[] v = new int[2];
            
            for (int i = a ; i < moves.length; i += 2){
                x[moves[i][0]] ++;
                y[moves[i][1]] ++;
                if (moves[i][0] == moves[i][1]){
                    v[0] ++;
                }
                if (moves[i][0] == 2 - moves[i][1]) {
                    v[1] ++;
                }
            }

            if (x[0] == 3 || x[1] == 3 ||x[2] == 3 || y [0] == 3 || y [1] == 3|| y [2] == 3 || v[0] == 3 || v[1] == 3){
                return a==0? "A":"B";
            }
        }
    
        return moves.length == 9? "Draw":"Pending";
    }
}

 

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