LeetCode - Arrays - Winner in Tic Tac Toe 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 " class Solution { public String tictactoe(int[][] moves) { String[][] ab_moves = new String[3][3]; int acounter = 0; int bcounter = 0; String result = null; for(int i=0;i<moves.length;i++){ int row = moves[i][0]; int col = moves[i][1]; if(i%2 == 0){ acounter++; ab_moves[row][col] = "A"; if(acounter >= 3) result = validateGame(ab_moves,row,col,"A"); } else{ bcounter++; ab_moves[row][col] = "B"; if(bcounter >= 3) result = validateGame(ab_moves,row,col,"B"); } if(result != null) return result; } if(result == null && moves.length == 9) result = "Draw"; else result = "Pending"; return result; } public String validateGame(String[][] ab_moves, int row, int col, String identifier){ String result = null; if((row == 0 && col == 0) || (row == 2 && col == 0) || (row == 0 && col == 2) || (row == 2 && col == 2) || (row ==1 && col == 1)){ if(identifier.equals(ab_moves[0][0]) && identifier.equals(ab_moves[1][1]) && identifier.equals(ab_moves[2][2])) result = identifier; else if(identifier.equals(ab_moves[0][2]) && identifier.equals(ab_moves[1][1]) && identifier.equals(ab_moves[2][0])) result = identifier; else result = null; } if(result == null){ for(int i=0;i<3;i++){ if(identifier.equals(ab_moves[row][i])) result = identifier; else{ result = null; break; } } if(result == null){ for(int i=0;i<3;i++){ if(identifier.equals(ab_moves[i][col])) result = identifier; else{ result = null; break; } } } } return result; } }