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.
A:
class Solution { public: string tictactoe(vector<vector<int>>& moves) { vector<vector<char>> T(3, vector<char>(3)); for(int i =0;i<moves.size();i++){ auto move = moves[i]; int x = move[0], y = move[1]; if(i%2==0) T[x][y] = 'X'; else T[x][y] = 'O'; if(isWin(T, x, y)){ return (i%2==0) ? "A" : "B"; } } return moves.size()<9? "Pending" : "Draw"; } private: bool isWin(vector<vector<char>> &T, int x ,int y){ char ch = T[x][y]; // check row int c = 0; for(int i=0;i<3;i++) if(T[i][y] == ch) c++; if(c==3) return true; // check col c = 0; for(int j=0;j<3;j++) if(T[x][j] == ch) c++; if(c==3) return true; // check \ diagnal if(x==y){ c = 0; for(int i =0;i<3;i++) if(T[i][i] == ch) c++; if(c==3) return true; } // check / diagnal if(x+y==2){ c = 0; for(int i =0;i<3;i++) if(T[i][2-i] == ch) c++; if(c==3) return true; } return false; } };
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