java - 用於確定Tic Tac Toe遊戲結束的算法




algorithm tic-tac-toe (14)

Constant time O(8), on average 4 short AND's. Player = short number. Needs additional checks for making sure move is valid.

// O(8)
boolean isWinner(short X) {
    for (int i = 0; i < 8; i++)
        if ((X & winCombinations[i]) == winCombinations[i])
            return true;
    return false;
}

short[] winCombinations = new short[]{
  7, 7 << 3, 7 << 6, // horizontal
  73, 73 << 1, 73 << 2, // vertical
  273, // diagonal
  84   // anti-diagonal
};

for (short X = 0; X < 511; X++)
   System.out.println(isWinner(X));

我用Java編寫了一個tic-tac-toe遊戲,我目前確定遊戲結束的方法解釋了遊戲結束時的下列可能場景:

  1. 董事會已滿,尚未宣布獲勝者:遊戲是平局。
  2. 克羅斯贏了。
  3. 圈子贏了。

不幸的是,為此,它從表中讀取預定義的這些場景集。 考慮到棋盤上只有9個空格,這並不一定是不好的,因此桌子有點小,但是有更好的算法確定遊戲是否結束? 確定某人是否獲勝是問題的癥結所在,因為檢查9個空間是否已滿是微不足道的。

表格方法可能是解決方案,但如果不是,那是什麼? 另外,如果董事會不是大小n=9 ? 如果它是一個更大的棋盤,比如n=16n=25等等,導致連續放置物品的數量取勝為x=4x=5等等,會怎樣? 用於所有n = { 9, 16, 25, 36 ... }通用算法?


How about a following approach for 9 slots? Declare 9 integer variables for a 3x3 matrix (a1,a2....a9) where a1,a2,a3 represent row-1 and a1,a4,a7 would form column-1 (you get the idea). Use '1' to indicate Player-1 and '2' to indicate Player-2.

There are 8 possible win combinations: Win-1: a1+a2+a3 (answer could be 3 or 6 based on which player won) Win-2: a4+a5+a6 Win-3: a7+a8+a9 Win-4: a1+a4+a7 .... Win-7: a1+a5+a9 Win-8: a3+a5+a7

Now we know that if player one crosses a1 then we need to reevaluate sum of 3 variables: Win-1, Win-4 and Win-7. Whichever 'Win-?' variables reaches 3 or 6 first wins the game. If Win-1 variable reaches 6 first then Player-2 wins.

I do understand that this solution is not scalable easily.


If you have boarder field 5*5 for examle, I used next method of checking:

public static boolean checkWin(char symb) {
  int SIZE = 5;

        for (int i = 0; i < SIZE-1; i++) {
            for (int j = 0; j <SIZE-1 ; j++) {
                //vertical checking
            if (map[0][j] == symb && map[1][j] == symb && map[2][j] == symb && map[3][j] == symb && map[4][j] == symb) return true;      // j=0
            }
            //horisontal checking
            if(map[i][0] == symb && map[i][1] == symb && map[i][2] == symb && map[i][3] == symb && map[i][4] == symb) return true;  // i=0
        }
        //diagonal checking (5*5)
        if (map[0][0] == symb && map[1][1] == symb && map[2][2] == symb && map[3][3] == symb && map[4][4] == symb) return true;
        if (map[4][0] == symb && map[3][1] == symb && map[2][2] == symb && map[1][3] == symb && map[0][4] == symb) return true;

        return false; 
        }

I think, it's more clear, but probably is not the most optimal way.


This is a really simple way to check.

    public class Game() { 

    Game player1 = new Game('x');
    Game player2 = new Game('o');

    char piece;

    Game(char piece) {
       this.piece = piece;
    }

public void checkWin(Game player) {

    // check horizontal win
    for (int i = 0; i <= 6; i += 3) {

        if (board[i] == player.piece &&
                board[i + 1] == player.piece &&
                board[i + 2] == player.piece)
            endGame(player);
    }

    // check vertical win
    for (int i = 0; i <= 2; i++) {

        if (board[i] == player.piece &&
                board[i + 3] == player.piece &&
                board[i + 6] == player.piece)
            endGame(player);
    }

    // check diagonal win
    if ((board[0] == player.piece &&
            board[4] == player.piece &&
            board[8] == player.piece) ||
            board[2] == player.piece &&
            board[4] == player.piece &&
            board[6] == player.piece)
        endGame(player);
    }

}


下面是我提出的解決方案,它將符號存儲為字符,並使用char的int值判斷X或O是否贏了(看裁判的代碼)

public class TicTacToe {
    public static final char BLANK = '\u0000';
    private final char[][] board;
    private int moveCount;
    private Referee referee;

    public TicTacToe(int gridSize) {
        if (gridSize < 3)
            throw new IllegalArgumentException("TicTacToe board size has to be minimum 3x3 grid");
        board = new char[gridSize][gridSize];
        referee = new Referee(gridSize);
    }

    public char[][] displayBoard() {
        return board.clone();
    }

    public String move(int x, int y) {
        if (board[x][y] != BLANK)
            return "(" + x + "," + y + ") is already occupied";
        board[x][y] = whoseTurn();
        return referee.isGameOver(x, y, board[x][y], ++moveCount);
    }

    private char whoseTurn() {
        return moveCount % 2 == 0 ? 'X' : 'O';
    }

    private class Referee {
        private static final int NO_OF_DIAGONALS = 2;
        private static final int MINOR = 1;
        private static final int PRINCIPAL = 0;
        private final int gridSize;
        private final int[] rowTotal;
        private final int[] colTotal;
        private final int[] diagonalTotal;

        private Referee(int size) {
            gridSize = size;
            rowTotal = new int[size];
            colTotal = new int[size];
            diagonalTotal = new int[NO_OF_DIAGONALS];
        }

        private String isGameOver(int x, int y, char symbol, int moveCount) {
            if (isWinningMove(x, y, symbol))
                return symbol + " won the game!";
            if (isBoardCompletelyFilled(moveCount))
                return "Its a Draw!";
            return "continue";
        }

        private boolean isBoardCompletelyFilled(int moveCount) {
            return moveCount == gridSize * gridSize;
        }

        private boolean isWinningMove(int x, int y, char symbol) {
            if (isPrincipalDiagonal(x, y) && allSymbolsMatch(symbol, diagonalTotal, PRINCIPAL))
                return true;
            if (isMinorDiagonal(x, y) && allSymbolsMatch(symbol, diagonalTotal, MINOR))
                return true;
            return allSymbolsMatch(symbol, rowTotal, x) || allSymbolsMatch(symbol, colTotal, y);
        }

        private boolean allSymbolsMatch(char symbol, int[] total, int index) {
            total[index] += symbol;
            return total[index] / gridSize == symbol;
        }

        private boolean isPrincipalDiagonal(int x, int y) {
            return x == y;
        }

        private boolean isMinorDiagonal(int x, int y) {
            return x + y == gridSize - 1;
        }
    }
}

另外這裡是我的單元測試來驗證它實際工作

import static com.agilefaqs.tdd.demo.TicTacToe.BLANK;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class TicTacToeTest {
    private TicTacToe game = new TicTacToe(3);

    @Test
    public void allCellsAreEmptyInANewGame() {
        assertBoardIs(new char[][] { { BLANK, BLANK, BLANK },
                { BLANK, BLANK, BLANK },
                { BLANK, BLANK, BLANK } });
    }

    @Test(expected = IllegalArgumentException.class)
    public void boardHasToBeMinimum3x3Grid() {
        new TicTacToe(2);
    }

    @Test
    public void firstPlayersMoveMarks_X_OnTheBoard() {
        assertEquals("continue", game.move(1, 1));
        assertBoardIs(new char[][] { { BLANK, BLANK, BLANK },
                { BLANK, 'X', BLANK },
                { BLANK, BLANK, BLANK } });
    }

    @Test
    public void secondPlayersMoveMarks_O_OnTheBoard() {
        game.move(1, 1);
        assertEquals("continue", game.move(2, 2));
        assertBoardIs(new char[][] { { BLANK, BLANK, BLANK },
                { BLANK, 'X', BLANK },
                { BLANK, BLANK, 'O' } });
    }

    @Test
    public void playerCanOnlyMoveToAnEmptyCell() {
        game.move(1, 1);
        assertEquals("(1,1) is already occupied", game.move(1, 1));
    }

    @Test
    public void firstPlayerWithAllSymbolsInOneRowWins() {
        game.move(0, 0);
        game.move(1, 0);
        game.move(0, 1);
        game.move(2, 1);
        assertEquals("X won the game!", game.move(0, 2));
    }

    @Test
    public void firstPlayerWithAllSymbolsInOneColumnWins() {
        game.move(1, 1);
        game.move(0, 0);
        game.move(2, 1);
        game.move(1, 0);
        game.move(2, 2);
        assertEquals("O won the game!", game.move(2, 0));
    }

    @Test
    public void firstPlayerWithAllSymbolsInPrincipalDiagonalWins() {
        game.move(0, 0);
        game.move(1, 0);
        game.move(1, 1);
        game.move(2, 1);
        assertEquals("X won the game!", game.move(2, 2));
    }

    @Test
    public void firstPlayerWithAllSymbolsInMinorDiagonalWins() {
        game.move(0, 2);
        game.move(1, 0);
        game.move(1, 1);
        game.move(2, 1);
        assertEquals("X won the game!", game.move(2, 0));
    }

    @Test
    public void whenAllCellsAreFilledTheGameIsADraw() {
        game.move(0, 2);
        game.move(1, 1);
        game.move(1, 0);
        game.move(2, 1);
        game.move(2, 2);
        game.move(0, 0);
        game.move(0, 1);
        game.move(1, 2);
        assertEquals("Its a Draw!", game.move(2, 0));
    }

    private void assertBoardIs(char[][] expectedBoard) {
        assertArrayEquals(expectedBoard, game.displayBoard());
    }
}

Full solution: https://github.com/nashjain/tictactoe/tree/master/java


下面是我為JavaScript編寫的項目編寫的解決方案。 如果您不介意少數陣列的內存成本,那麼這可能是您找到的最快,最簡單的解決方案。 它假定你知道最後一步的位置。

/*
 * Determines if the last move resulted in a win for either player
 * board: is an array representing the board
 * lastMove: is the boardIndex of the last (most recent) move
 *  these are the boardIndexes:
 *
 *   0 | 1 | 2
 *  ---+---+---
 *   3 | 4 | 5
 *  ---+---+---
 *   6 | 7 | 8
 * 
 * returns true if there was a win
 */
var winLines = [
    [[1, 2], [4, 8], [3, 6]],
    [[0, 2], [4, 7]],
    [[0, 1], [4, 6], [5, 8]],
    [[4, 5], [0, 6]],
    [[3, 5], [0, 8], [2, 6], [1, 7]],
    [[3, 4], [2, 8]],
    [[7, 8], [2, 4], [0, 3]],
    [[6, 8], [1, 4]],
    [[6, 7], [0, 4], [2, 5]]
];
function isWinningMove(board, lastMove) {
    var player = board[lastMove];
    for (var i = 0; i < winLines[lastMove].length; i++) {
        var line = winLines[lastMove][i];
        if(player === board[line[0]] && player === board[line[1]]) {
            return true;
        }
    }
    return false;
}

只有在X或O進行了最近的移動後,才會發生勝出動作,因此您只能使用該移動中包含的可選診斷來搜索行/列,以在嘗試確定獲勝的棋盤時限制搜索空間。 另外,因為如果最後一步移動不是贏得移動,那麼在抽取井字遊戲中有一定數量的移動,所以它默認為抽獎遊戲。

編輯:這個代碼是n個棋盤n連贏(3x3棋盤連續3連續等)

編輯:添加代碼來檢查anti diag,我找不到一個非循環的方式來確定點是否在反diag,這就是為什麼該步驟失踪

public class TripleT {

    enum State{Blank, X, O};

    int n = 3;
    State[][] board = new State[n][n];
    int moveCount;

    void Move(int x, int y, State s){
        if(board[x][y] == State.Blank){
            board[x][y] = s;
        }
        moveCount++;

        //check end conditions

        //check col
        for(int i = 0; i < n; i++){
            if(board[x][i] != s)
                break;
            if(i == n-1){
                //report win for s
            }
        }

        //check row
        for(int i = 0; i < n; i++){
            if(board[i][y] != s)
                break;
            if(i == n-1){
                //report win for s
            }
        }

        //check diag
        if(x == y){
            //we're on a diagonal
            for(int i = 0; i < n; i++){
                if(board[i][i] != s)
                    break;
                if(i == n-1){
                    //report win for s
                }
            }
        }

        //check anti diag (thanks rampion)
        if(x + y == n - 1){
            for(int i = 0; i < n; i++){
                if(board[i][(n-1)-i] != s)
                    break;
                if(i == n-1){
                    //report win for s
                }
            }
        }

        //check draw
        if(moveCount == (Math.pow(n, 2) - 1)){
            //report draw
        }
    }
}

在我的一次採訪中,我被問到同樣的問題。 我的想法:用0初始化矩陣。保留3個數組1)sum_row(size n)2)sum_column(size n)3)對角線(size 2)

對於(X)的每次移動,將值減1,對於每次移動(0),將其遞增1.在任何點,如果在當前移動中修改過的行/列/對角線的和為-3或+ 3意味著有人贏得了比賽。 對於平局,我們可以使用上面的方法來保持moveCount變量。

你認為我錯過了什麼嗎?

編輯:相同可以用於nxn矩陣。 總和應該是+3或-3。


如果電路板是n × n,則有n行, n列和2個對角線。 檢查全部X或全部O的每一個以找到勝利者。

如果只需要x < n個連續的方塊贏得勝利,那麼它會更複雜一點。 最明顯的解決方案是檢查每個x × x方格以獲得勝利者。 這裡有一些代碼可以證明這一點。

(我沒有真正測試這個*咳嗽*,但是它在第一次嘗試編譯了,對我來說!)

public class TicTacToe
{
    public enum Square { X, O, NONE }

    /**
     * Returns the winning player, or NONE if the game has
     * finished without a winner, or null if the game is unfinished.
     */
    public Square findWinner(Square[][] board, int lengthToWin) {
        // Check each lengthToWin x lengthToWin board for a winner.    
        for (int top = 0; top <= board.length - lengthToWin; ++top) {
            int bottom = top + lengthToWin - 1;

            for (int left = 0; left <= board.length - lengthToWin; ++left) {
                int right = left + lengthToWin - 1;

                // Check each row.
                nextRow: for (int row = top; row <= bottom; ++row) {
                    if (board[row][left] == Square.NONE) {
                        continue;
                    }

                    for (int col = left; col <= right; ++col) {
                        if (board[row][col] != board[row][left]) {
                            continue nextRow;
                        }
                    }

                    return board[row][left];
                }

                // Check each column.
                nextCol: for (int col = left; col <= right; ++col) {
                    if (board[top][col] == Square.NONE) {
                        continue;
                    }

                    for (int row = top; row <= bottom; ++row) {
                        if (board[row][col] != board[top][col]) {
                            continue nextCol;
                        }
                    }

                    return board[top][col];
                }

                // Check top-left to bottom-right diagonal.
                diag1: if (board[top][left] != Square.NONE) {
                    for (int i = 1; i < lengthToWin; ++i) {
                        if (board[top+i][left+i] != board[top][left]) {
                            break diag1;
                        }
                    }

                    return board[top][left];
                }

                // Check top-right to bottom-left diagonal.
                diag2: if (board[top][right] != Square.NONE) {
                    for (int i = 1; i < lengthToWin; ++i) {
                        if (board[top+i][right-i] != board[top][right]) {
                            break diag2;
                        }
                    }

                    return board[top][right];
                }
            }
        }

        // Check for a completely full board.
        boolean isFull = true;

        full: for (int row = 0; row < board.length; ++row) {
            for (int col = 0; col < board.length; ++col) {
                if (board[row][col] == Square.NONE) {
                    isFull = false;
                    break full;
                }
            }
        }

        // The board is full.
        if (isFull) {
            return Square.NONE;
        }
        // The board is not full and we didn't find a solution.
        else {
            return null;
        }
    }
}

我不太了解Java,但我確實知道C,所以我嘗試了adk的魔方 (與Hardwareguy的搜索限制一起 )。

// tic-tac-toe.c
// to compile:
//  % gcc -o tic-tac-toe tic-tac-toe.c
// to run:
//  % ./tic-tac-toe
#include <stdio.h>

// the two types of marks available
typedef enum { Empty=2, X=0, O=1, NumMarks=2 } Mark;
char const MarkToChar[] = "XO ";

// a structure to hold the sums of each kind of mark
typedef struct { unsigned char of[NumMarks]; } Sum;

// a cell in the board, which has a particular value
#define MAGIC_NUMBER 15
typedef struct {
  Mark mark;
  unsigned char const value;
  size_t const num_sums;
  Sum * const sums[4];
} Cell;

#define NUM_ROWS 3
#define NUM_COLS 3

// create a sum for each possible tic-tac-toe
Sum row[NUM_ROWS] = {0};
Sum col[NUM_COLS] = {0};
Sum nw_diag = {0};
Sum ne_diag = {0};

// initialize the board values so any row, column, or diagonal adds to
// MAGIC_NUMBER, and so they each record their sums in the proper rows, columns,
// and diagonals
Cell board[NUM_ROWS][NUM_COLS] = { 
  { 
    { Empty, 8, 3, { &row[0], &col[0], &nw_diag } },
    { Empty, 1, 2, { &row[0], &col[1] } },
    { Empty, 6, 3, { &row[0], &col[2], &ne_diag } },
  },
  { 
    { Empty, 3, 2, { &row[1], &col[0] } },
    { Empty, 5, 4, { &row[1], &col[1], &nw_diag, &ne_diag } },
    { Empty, 7, 2, { &row[1], &col[2] } },
  },
  { 
    { Empty, 4, 3, { &row[2], &col[0], &ne_diag } },
    { Empty, 9, 2, { &row[2], &col[1] } },
    { Empty, 2, 3, { &row[2], &col[2], &nw_diag } },
  }
};

// print the board
void show_board(void)
{
  size_t r, c;
  for (r = 0; r < NUM_ROWS; r++) 
  {
    if (r > 0) { printf("---+---+---\n"); }
    for (c = 0; c < NUM_COLS; c++) 
    {
      if (c > 0) { printf("|"); }
      printf(" %c ", MarkToChar[board[r][c].mark]);
    }
    printf("\n");
  }
}


// run the game, asking the player for inputs for each side
int main(int argc, char * argv[])
{
  size_t m;
  show_board();
  printf("Enter moves as \"<row> <col>\" (no quotes, zero indexed)\n");
  for( m = 0; m < NUM_ROWS * NUM_COLS; m++ )
  {
    Mark const mark = (Mark) (m % NumMarks);
    size_t c, r;

    // read the player's move
    do
    {
      printf("%c's move: ", MarkToChar[mark]);
      fflush(stdout);
      scanf("%d %d", &r, &c);
      if (r >= NUM_ROWS || c >= NUM_COLS)
      {
        printf("illegal move (off the board), try again\n");
      }
      else if (board[r][c].mark != Empty)
      {
        printf("illegal move (already taken), try again\n");
      }
      else
      {
        break;
      }
    }
    while (1);

    {
      Cell * const cell = &(board[r][c]);
      size_t s;

      // update the board state
      cell->mark = mark;
      show_board();

      // check for tic-tac-toe
      for (s = 0; s < cell->num_sums; s++)
      {
        cell->sums[s]->of[mark] += cell->value;
        if (cell->sums[s]->of[mark] == MAGIC_NUMBER)
        {
          printf("tic-tac-toe! %c wins!\n", MarkToChar[mark]);
          goto done;
        }
      }
    }
  }
  printf("stalemate... nobody wins :(\n");
done:
  return 0;
}

它編譯和測試良好。

% gcc -o tic-tac-toe tic-tac-toe.c
% ./tic-tac-toe
     |   |
  ---+---+---
     |   |
  ---+---+---
     |   |
  Enter moves as " " (no quotes, zero indexed)
  X's move: 1 2
     |   |
  ---+---+---
     |   | X
  ---+---+---
     |   |
  O's move: 1 2
  illegal move (already taken), try again
  O's move: 3 3
  illegal move (off the board), try again
  O's move: 2 2
     |   |
  ---+---+---
     |   | X
  ---+---+---
     |   | O
  X's move: 1 0
     |   |
  ---+---+---
   X |   | X
  ---+---+---
     |   | O
  O's move: 1 1
     |   |
  ---+---+---
   X | O | X
  ---+---+---
     |   | O
  X's move: 0 0
   X |   |
  ---+---+---
   X | O | X
  ---+---+---
     |   | O
  O's move: 2 0
   X |   |
  ---+---+---
   X | O | X
  ---+---+---
   O |   | O
  X's move: 2 1
   X |   |
  ---+---+---
   X | O | X
  ---+---+---
   O | X | O
  O's move: 0 2
   X |   | O
  ---+---+---
   X | O | X
  ---+---+---
   O | X | O
  tic-tac-toe! O wins!
% ./tic-tac-toe
     |   |
  ---+---+---
     |   |
  ---+---+---
     |   |
  Enter moves as " " (no quotes, zero indexed)
  X's move: 0 0
   X |   |
  ---+---+---
     |   |
  ---+---+---
     |   |
  O's move: 0 1
   X | O |
  ---+---+---
     |   |
  ---+---+---
     |   |
  X's move: 0 2
   X | O | X
  ---+---+---
     |   |
  ---+---+---
     |   |
  O's move: 1 0
   X | O | X
  ---+---+---
   O |   |
  ---+---+---
     |   |
  X's move: 1 1
   X | O | X
  ---+---+---
   O | X |
  ---+---+---
     |   |
  O's move: 2 0
   X | O | X
  ---+---+---
   O | X |
  ---+---+---
   O |   |
  X's move: 2 1
   X | O | X
  ---+---+---
   O | X |
  ---+---+---
   O | X |
  O's move: 2 2
   X | O | X
  ---+---+---
   O | X |
  ---+---+---
   O | X | O
  X's move: 1 2
   X | O | X
  ---+---+---
   O | X | X
  ---+---+---
   O | X | O
  stalemate... nobody wins :(
%

這很有趣,謝謝!

實際上,考慮一下,你不需要一個神奇的方塊,只需要每行/一列/對角線的計數。 這比將廣場幻方變為n × n矩陣容易一些,因為你只需要計算到n


我喜歡這種算法,因為它使用了1x9與3x3的電路板表示。

private int[] board = new int[9];
private static final int[] START = new int[] { 0, 3, 6, 0, 1, 2, 0, 2 };
private static final int[] INCR  = new int[] { 1, 1, 1, 3, 3, 3, 4, 2 };
private static int SIZE = 3;
/**
 * Determines if there is a winner in tic-tac-toe board.
 * @return {@code 0} for draw, {@code 1} for 'X', {@code -1} for 'Y'
 */
public int hasWinner() {
    for (int i = 0; i < START.length; i++) {
        int sum = 0;
        for (int j = 0; j < SIZE; j++) {
            sum += board[START[i] + j * INCR[i]];
        }
        if (Math.abs(sum) == SIZE) {
            return sum / SIZE;
        }
    }
    return 0;
}

我在行,列,對角線檢查中做了一些優化。 如果我們需要檢查特定的列或對角線,它主要決定於第一個嵌套循環。 所以,我們避免檢查列或對角線節省時間。 當電路板尺寸更大且沒有填充大量單元時,這會產生很大影響。

這是為此的Java代碼。

    int gameState(int values[][], int boardSz) {


    boolean colCheckNotRequired[] = new boolean[boardSz];//default is false
    boolean diag1CheckNotRequired = false;
    boolean diag2CheckNotRequired = false;
    boolean allFilled = true;


    int x_count = 0;
    int o_count = 0;
    /* Check rows */
    for (int i = 0; i < boardSz; i++) {
        x_count = o_count = 0;
        for (int j = 0; j < boardSz; j++) {
            if(values[i][j] == x_val)x_count++;
            if(values[i][j] == o_val)o_count++;
            if(values[i][j] == 0)
            {
                colCheckNotRequired[j] = true;
                if(i==j)diag1CheckNotRequired = true;
                if(i + j == boardSz - 1)diag2CheckNotRequired = true;
                allFilled = false;
                //No need check further
                break;
            }
        }
        if(x_count == boardSz)return X_WIN;
        if(o_count == boardSz)return O_WIN;         
    }


    /* check cols */
    for (int i = 0; i < boardSz; i++) {
        x_count = o_count = 0;
        if(colCheckNotRequired[i] == false)
        {
            for (int j = 0; j < boardSz; j++) {
                if(values[j][i] == x_val)x_count++;
                if(values[j][i] == o_val)o_count++;
                //No need check further
                if(values[i][j] == 0)break;
            }
            if(x_count == boardSz)return X_WIN;
            if(o_count == boardSz)return O_WIN;
        }
    }

    x_count = o_count = 0;
    /* check diagonal 1 */
    if(diag1CheckNotRequired == false)
    {
        for (int i = 0; i < boardSz; i++) {
            if(values[i][i] == x_val)x_count++;
            if(values[i][i] == o_val)o_count++;
            if(values[i][i] == 0)break;
        }
        if(x_count == boardSz)return X_WIN;
        if(o_count == boardSz)return O_WIN;
    }

    x_count = o_count = 0;
    /* check diagonal 2 */
    if( diag2CheckNotRequired == false)
    {
        for (int i = boardSz - 1,j = 0; i >= 0 && j < boardSz; i--,j++) {
            if(values[j][i] == x_val)x_count++;
            if(values[j][i] == o_val)o_count++;
            if(values[j][i] == 0)break;
        }
        if(x_count == boardSz)return X_WIN;
        if(o_count == boardSz)return O_WIN;
        x_count = o_count = 0;
    }

    if( allFilled == true)
    {
        for (int i = 0; i < boardSz; i++) {
            for (int j = 0; j < boardSz; j++) {
                if (values[i][j] == 0) {
                    allFilled = false;
                    break;
                }
            }

            if (allFilled == false) {
                break;
            }
        }
    }

    if (allFilled)
        return DRAW;

    return INPROGRESS;
}

這個偽代碼如何:

玩家在位置(x,y)放下一塊棋子後:

col=row=diag=rdiag=0
winner=false
for i=1 to n
  if cell[x,i]=player then col++
  if cell[i,y]=player then row++
  if cell[i,i]=player then diag++
  if cell[i,n-i+1]=player then rdiag++
if row=n or col=n or diag=n or rdiag=n then winner=true

我會使用一個char [n,n]數組,其中O,X和空格為空。

  1. 簡單。
  2. 一個循環。
  3. 五個簡單變量:4個整數和一個布爾值。
  4. 可以縮放到n的任意大小。
  5. 只檢查當前件。
  6. 沒有魔法。 :)

這與Osama ALASSIRY的答案類似,但它為線性空間和恆定時間交易恆定空間和線性時間。 也就是說,初始化後沒有循環。

為每行,每列和兩個對角線(對角線和反對角線)初始化一對(0,0) )。 這些對錶示相應的行,列或對角線中的塊的累積(sum,sum) ,其中

A piece from player A has value (1,0)
A piece from player B has value (0,1)

當玩家放置棋子時,更新相應的行對,列對和對角線對(如果在對角線上)。 如果任何新更新的行,列或對角線對等於(n,0)(0,n)則A或B分別獲勝。

漸近分析:

O(1) time (per move)
O(n) space (overall)

對於內存使用,您使用4*(n+1)整數。

two_elements*n_rows + two_elements*n_columns +
two_elements*two_diagonals = 4*n + 4 integers = 4(n+1) integers

練習:你能看到如何測試O(1)每次移動的平局嗎? 如果是這樣,你可以提前結束比賽。





tic-tac-toe