LeetCode - Design Tic-Tac-Toe

Design a Tic-tac-toe game that is played between two players on a n x n grid.
You may assume the following rules:
  1. A move is guaranteed to be valid and is placed on an empty block.
  2. Once a winning condition is reached, no more moves is allowed.
  3. A player who succeeds in placing n of their marks in a horizontal, vertical, or diagonal row wins the game.
Example:
Given n = 3, assume that player 1 is "X" and player 2 is "O" in the board.

TicTacToe toe = new TicTacToe(3);

toe.move(0, 0, 1); -> Returns 0 (no one wins)
|X| | |
| | | |    // Player 1 makes a move at (0, 0).
| | | |

toe.move(0, 2, 2); -> Returns 0 (no one wins)
|X| |O|
| | | |    // Player 2 makes a move at (0, 2).
| | | |

toe.move(2, 2, 1); -> Returns 0 (no one wins)
|X| |O|
| | | |    // Player 1 makes a move at (2, 2).
| | |X|

toe.move(1, 1, 2); -> Returns 0 (no one wins)
|X| |O|
| |O| |    // Player 2 makes a move at (1, 1).
| | |X|

toe.move(2, 0, 1); -> Returns 0 (no one wins)
|X| |O|
| |O| |    // Player 1 makes a move at (2, 0).
|X| |X|

toe.move(1, 0, 2); -> Returns 0 (no one wins)
|X| |O|
|O|O| |    // Player 2 makes a move at (1, 0).
|X| |X|

toe.move(2, 1, 1); -> Returns 1 (player 1 wins)
|X| |O|
|O|O| |    // Player 1 makes a move at (2, 1).
|X|X|X|
Follow up:
Could you do better than O(n2) per move() operation?
Java Solution :
class TicTacToe {
        int[] rowCounter;
        int[] colCounter;
        int diagLeft;
        int diagRight;
        int n;
    /** Initialize your data structure here. */
    public TicTacToe(int n) {
        this.n = n;
         rowCounter = new int[n];
         colCounter = new int[n];
         diagLeft = 0;
         diagRight = 0;
    }
    
    /** Player {player} makes a move at ({row}, {col}).
        @param row The row of the board.
        @param col The column of the board.
        @param player The player, can be either 1 or 2.
        @return The current winning condition, can be either:
                0: No one wins.
                1: Player 1 wins.
                2: Player 2 wins. */
    public int move(int row, int col, int player) {
        int move = (player == 1) ? 1 : -1;
        rowCounter[row] +=move;
        colCounter[col] +=move;
        if(row == col)
            diagLeft +=move;
        if(row == n-col-1)
            diagRight +=move;
        if(rowCounter[row] == n || diagLeft == n || diagRight== n || colCounter[col] == n)
            return 1;
        else if(rowCounter[row] == -n || diagLeft == -n || diagRight== -n || colCounter[col] == -n)return 2;
        else
            return 0; 
    }
}

/**
 * Your TicTacToe object will be instantiated and called as such:
 * TicTacToe obj = new TicTacToe(n);
 * int param_1 = obj.move(row,col,player);
 */

No comments:

Post a Comment

Featured Post

H1B Visa Stamping at US Consulate

  H1B Visa Stamping at US Consulate If you are outside of the US, you need to apply for US Visa at a US Consulate or a US Embassy and get H1...