最近我一直在iPhone上玩一款名为《Scramble》的游戏。有些人可能知道这个游戏叫拼字游戏。从本质上讲,当游戏开始时,你会得到一个字母矩阵:

F X I E
A M L O
E W B X
A S T U

The goal of the game is to find as many words as you can that can be formed by chaining letters together. You can start with any letter, and all the letters that surround it are fair game, and then once you move on to the next letter, all the letters that surround that letter are fair game, except for any previously used letters. So in the grid above, for example, I could come up with the words LOB, TUX, SEA, FAME, etc. Words must be at least 3 characters, and no more than NxN characters, which would be 16 in this game but can vary in some implementations. While this game is fun and addictive, I am apparently not very good at it and I wanted to cheat a little bit by making a program that would give me the best possible words (the longer the word the more points you get).

(来源:boggled.org)

不幸的是,我不太擅长算法或它们的效率等等。我的第一次尝试使用一个像这样的字典(约2.3MB),并进行线性搜索,试图匹配字典条目的组合。这需要花费很长时间来找到可能的单词,因为你每轮只有2分钟的时间,这是不够的。

我很有兴趣看看是否有任何Stackoverflowers可以提出更有效的解决方案。我主要是在寻找使用三大p的解决方案:Python、PHP和Perl,尽管任何使用Java或c++的东西也很酷,因为速度是至关重要的。

目前的解决方案:

Adam Rosenfield, Python, ~20岁 John Fouhy, Python, ~3秒 Kent Fredric, Perl, ~1s Darius Bacon, Python, ~1s rvarcher, VB。净,~ 1 s Paolo Bergantino, PHP(实时链接),~5s(本地~2s)


当前回答

import java.util.HashSet;
import java.util.Set;

/**
 * @author Sujeet Kumar (mrsujeet@gmail.com) It prints out all strings that can
 *         be formed by moving left, right, up, down, or diagonally and exist in
 *         a given dictionary , without repeating any cell. Assumes words are
 *         comprised of lower case letters. Currently prints words as many times
 *         as they appear, not just once. *
 */

public class BoggleGame 
{
  /* A sample 4X4 board/2D matrix */
  private static char[][] board = { { 's', 'a', 's', 'g' },
                                  { 'a', 'u', 't', 'h' }, 
                                  { 'r', 't', 'j', 'e' },
                                  { 'k', 'a', 'h', 'e' }
};

/* A sample dictionary which contains unique collection of words */
private static Set<String> dictionary = new HashSet<String>();

private static boolean[][] visited = new boolean[board.length][board[0].length];

public static void main(String[] arg) {
    dictionary.add("sujeet");
    dictionary.add("sarthak");
    findWords();

}

// show all words, starting from each possible starting place
private static void findWords() {
    for (int i = 0; i < board.length; i++) {
        for (int j = 0; j < board[i].length; j++) {
            StringBuffer buffer = new StringBuffer();
            dfs(i, j, buffer);
        }

    }

}

// run depth first search starting at cell (i, j)
private static void dfs(int i, int j, StringBuffer buffer) {
    /*
     * base case: just return in recursive call when index goes out of the
     * size of matrix dimension
     */
    if (i < 0 || j < 0 || i > board.length - 1 || j > board[i].length - 1) {
        return;
    }

    /*
     * base case: to return in recursive call when given cell is already
     * visited in a given string of word
     */
    if (visited[i][j] == true) { // can't visit a cell more than once
        return;
    }

    // not to allow a cell to reuse
    visited[i][j] = true;

    // combining cell character with other visited cells characters to form
    // word a potential word which may exist in dictionary
    buffer.append(board[i][j]);

    // found a word in dictionary. Print it.
    if (dictionary.contains(buffer.toString())) {
        System.out.println(buffer);
    }

    /*
     * consider all neighbors.For a given cell considering all adjacent
     * cells in horizontal, vertical and diagonal direction
     */
    for (int k = i - 1; k <= i + 1; k++) {
        for (int l = j - 1; l <= j + 1; l++) {
            dfs(k, l, buffer);

        }

    }
    buffer.deleteCharAt(buffer.length() - 1);
    visited[i][j] = false;
  }
}

其他回答

我知道我已经非常晚了,但是我之前用PHP做了一个——只是为了好玩……

http://www.lostsockdesign.com.au/sandbox/boggle/index.php?letters=fxieamloewbxastu 在0.90108秒内找到75个单词(133分)

F……X . .我 .............. E ............... 一个 ...................................... 米 .............................. L ............................ O ............................... E .................... W ............................ B .......................... X 一个 .................. 年代 .................................................. T ................. U…

给出了一些程序实际在做什么的指示-每个字母是它开始查看模式的地方,而每个'。这显示了中国试图走的一条道路。越多越好。“它搜索得越远。

如果你想要密码,请告诉我…这是一个可怕的PHP和HTML的混合体,从来没有想过要看到阳光,所以我不敢在这里张贴:P

我已经在OCaml中实现了一个解决方案。它将字典预编译为trie,并使用双字母序列频率来消除单词中永远不会出现的边,以进一步加快处理速度。

它在0.35ms内解决了示例板的问题(额外的6ms启动时间主要与将trie加载到内存有关)。

找到的解决方案:

["swami"; "emile"; "limbs"; "limbo"; "limes"; "amble"; "tubs"; "stub";
 "swam"; "semi"; "seam"; "awes"; "buts"; "bole"; "boil"; "west"; "east";
 "emil"; "lobs"; "limb"; "lime"; "lima"; "mesa"; "mews"; "mewl"; "maws";
 "milo"; "mile"; "awes"; "amie"; "axle"; "elma"; "fame"; "ubs"; "tux"; "tub";
 "twa"; "twa"; "stu"; "saw"; "sea"; "sew"; "sea"; "awe"; "awl"; "but"; "btu";
 "box"; "bmw"; "was"; "wax"; "oil"; "lox"; "lob"; "leo"; "lei"; "lie"; "mes";
 "mew"; "mae"; "maw"; "max"; "mil"; "mix"; "awe"; "awl"; "elm"; "eli"; "fax"]
import java.util.HashSet;
import java.util.Set;

/**
 * @author Sujeet Kumar (mrsujeet@gmail.com) It prints out all strings that can
 *         be formed by moving left, right, up, down, or diagonally and exist in
 *         a given dictionary , without repeating any cell. Assumes words are
 *         comprised of lower case letters. Currently prints words as many times
 *         as they appear, not just once. *
 */

public class BoggleGame 
{
  /* A sample 4X4 board/2D matrix */
  private static char[][] board = { { 's', 'a', 's', 'g' },
                                  { 'a', 'u', 't', 'h' }, 
                                  { 'r', 't', 'j', 'e' },
                                  { 'k', 'a', 'h', 'e' }
};

/* A sample dictionary which contains unique collection of words */
private static Set<String> dictionary = new HashSet<String>();

private static boolean[][] visited = new boolean[board.length][board[0].length];

public static void main(String[] arg) {
    dictionary.add("sujeet");
    dictionary.add("sarthak");
    findWords();

}

// show all words, starting from each possible starting place
private static void findWords() {
    for (int i = 0; i < board.length; i++) {
        for (int j = 0; j < board[i].length; j++) {
            StringBuffer buffer = new StringBuffer();
            dfs(i, j, buffer);
        }

    }

}

// run depth first search starting at cell (i, j)
private static void dfs(int i, int j, StringBuffer buffer) {
    /*
     * base case: just return in recursive call when index goes out of the
     * size of matrix dimension
     */
    if (i < 0 || j < 0 || i > board.length - 1 || j > board[i].length - 1) {
        return;
    }

    /*
     * base case: to return in recursive call when given cell is already
     * visited in a given string of word
     */
    if (visited[i][j] == true) { // can't visit a cell more than once
        return;
    }

    // not to allow a cell to reuse
    visited[i][j] = true;

    // combining cell character with other visited cells characters to form
    // word a potential word which may exist in dictionary
    buffer.append(board[i][j]);

    // found a word in dictionary. Print it.
    if (dictionary.contains(buffer.toString())) {
        System.out.println(buffer);
    }

    /*
     * consider all neighbors.For a given cell considering all adjacent
     * cells in horizontal, vertical and diagonal direction
     */
    for (int k = i - 1; k <= i + 1; k++) {
        for (int l = j - 1; l <= j + 1; l++) {
            dfs(k, l, buffer);

        }

    }
    buffer.deleteCharAt(buffer.length() - 1);
    visited[i][j] = false;
  }
}

我很快完美地解决了这个问题。我把它放进了一个安卓应用程序。在play store链接中查看视频,看看它是如何运作的。

单词作弊是一个应用程序,“破解”任何矩阵风格的文字游戏。这个应用程序 来帮我在文字混淆器上作弊。它可以用于单词搜索, 沙沙,单词,单词查找器,单词破解,拼字游戏,和更多!

在这里可以看到 https://play.google.com/store/apps/details?id=com.harris.wordcracker

在视频中查看应用程序的操作 https://www.youtube.com/watch?v=DL2974WmNAI

你可以把这个问题分成两部分:

某种搜索算法可以在网格中列举出可能的字符串。 一种测试字符串是否是有效单词的方法。

理想情况下,(2)还应该包括一种测试字符串是否是有效单词前缀的方法——这将允许您精简搜索并节省大量时间。

亚当·罗森菲尔德(Adam Rosenfield)的Trie是(2)的一个解决方案。它很优雅,可能是算法专家的首选,但有了现代语言和现代计算机,我们可能会更懒一点。此外,正如Kent所建议的,我们可以通过丢弃网格中没有字母的单词来减少字典的大小。这是一些蟒蛇:

def make_lookups(grid, fn='dict.txt'):
    # Make set of valid characters.
    chars = set()
    for word in grid:
        chars.update(word)

    words = set(x.strip() for x in open(fn) if set(x.strip()) <= chars)
    prefixes = set()
    for w in words:
        for i in range(len(w)+1):
            prefixes.add(w[:i])

    return words, prefixes

哇;常数时间前缀测试。加载你链接的字典需要几秒钟,但只有几秒钟:-)(注意words <= prefixes)

现在,对于第(1)部分,我倾向于用图表来思考。所以我将创建一个像这样的字典:

graph = { (x, y):set([(x0,y0), (x1,y1), (x2,y2)]), }

例如,graph[(x, y)]是你从位置(x, y)可以到达的坐标集。我还将添加一个虚拟节点None,它将连接到所有东西。

构建它有点笨拙,因为有8个可能的位置,你必须做边界检查。下面是一些相应笨拙的python代码:

def make_graph(grid):
    root = None
    graph = { root:set() }
    chardict = { root:'' }

    for i, row in enumerate(grid):
        for j, char in enumerate(row):
            chardict[(i, j)] = char
            node = (i, j)
            children = set()
            graph[node] = children
            graph[root].add(node)
            add_children(node, children, grid)

    return graph, chardict

def add_children(node, children, grid):
    x0, y0 = node
    for i in [-1,0,1]:
        x = x0 + i
        if not (0 <= x < len(grid)):
            continue
        for j in [-1,0,1]:
            y = y0 + j
            if not (0 <= y < len(grid[0])) or (i == j == 0):
                continue

            children.add((x,y))

这段代码还建立了一个字典映射(x,y)到相应的字符。这让我把一个位置列表转换成一个单词:

def to_word(chardict, pos_list):
    return ''.join(chardict[x] for x in pos_list)

最后,我们进行深度优先搜索。基本程序是:

搜索到达一个特定的节点。 检查到目前为止的路径是否可能是单词的一部分。如果不是,就不要进一步探索这个分支。 检查到目前为止的路径是否是一个单词。如果是,则添加到结果列表中。 探索迄今为止所有孩子未走的路。

Python:

def find_words(graph, chardict, position, prefix, results, words, prefixes):
    """ Arguments:
      graph :: mapping (x,y) to set of reachable positions
      chardict :: mapping (x,y) to character
      position :: current position (x,y) -- equals prefix[-1]
      prefix :: list of positions in current string
      results :: set of words found
      words :: set of valid words in the dictionary
      prefixes :: set of valid words or prefixes thereof
    """
    word = to_word(chardict, prefix)

    if word not in prefixes:
        return

    if word in words:
        results.add(word)

    for child in graph[position]:
        if child not in prefix:
            find_words(graph, chardict, child, prefix+[child], results, words, prefixes)

运行代码如下:

grid = ['fxie', 'amlo', 'ewbx', 'astu']
g, c = make_graph(grid)
w, p = make_lookups(grid)
res = set()
find_words(g, c, None, [], res, w, p)

检查保留区,看看答案。下面是为你的例子找到的单词列表,按大小排序:

 ['a', 'b', 'e', 'f', 'i', 'l', 'm', 'o', 's', 't',
 'u', 'w', 'x', 'ae', 'am', 'as', 'aw', 'ax', 'bo',
 'bu', 'ea', 'el', 'em', 'es', 'fa', 'ie', 'io', 'li',
 'lo', 'ma', 'me', 'mi', 'oe', 'ox', 'sa', 'se', 'st',
 'tu', 'ut', 'wa', 'we', 'xi', 'aes', 'ame', 'ami',
 'ase', 'ast', 'awa', 'awe', 'awl', 'blo', 'but', 'elb',
 'elm', 'fae', 'fam', 'lei', 'lie', 'lim', 'lob', 'lox',
 'mae', 'maw', 'mew', 'mil', 'mix', 'oil', 'olm', 'saw',
 'sea', 'sew', 'swa', 'tub', 'tux', 'twa', 'wae', 'was',
 'wax', 'wem', 'ambo', 'amil', 'amli', 'asem', 'axil',
 'axle', 'bleo', 'boil', 'bole', 'east', 'fame', 'limb',
 'lime', 'mesa', 'mewl', 'mile', 'milo', 'oime', 'sawt',
 'seam', 'seax', 'semi', 'stub', 'swam', 'twae', 'twas',
 'wame', 'wase', 'wast', 'weam', 'west', 'amble', 'awest',
 'axile', 'embox', 'limbo', 'limes', 'swami', 'embole',
 'famble', 'semble', 'wamble']

代码需要(字面上的)几秒钟来加载字典,但其余的在我的机器上是立即完成的。