对VB不感兴趣?:)我忍不住了。我解决这个问题的方法不同于这里提出的许多解决方案。

我的时间是:

将字典和单词前缀加载到哈希表:.5到1秒。 找单词:平均不到10毫秒。

编辑:web主机服务器上的字典加载时间比我的家用电脑长1到1.5秒。

我不知道随着服务器负载的增加，时间会恶化到什么程度。

我把我的解决方案写成了。net的网页。myvrad.com/boggle

我用的是原题中提到的字典。

字母在单词中不能重复使用。只找到3个字符或以上的单词。

我使用所有唯一的单词前缀和单词的哈希表，而不是一个trie。我不知道什么是trie，所以我学到了一些东西。除了完整的单词之外，创建单词前缀列表的想法最终使我的时间减少到一个可观的数字。

阅读代码注释以获得更多详细信息。

代码如下:

Imports System.Collections.Generic
Imports System.IO

Partial Class boggle_Default

    'Bob Archer, 4/15/2009

    'To avoid using a 2 dimensional array in VB I'm not using typical X,Y
    'coordinate iteration to find paths.
    '
    'I have locked the code into a 4 by 4 grid laid out like so:
    ' abcd
    ' efgh
    ' ijkl
    ' mnop
    ' 
    'To find paths the code starts with a letter from a to p then
    'explores the paths available around it. If a neighboring letter
    'already exists in the path then we don't go there.
    '
    'Neighboring letters (grid points) are hard coded into
    'a Generic.Dictionary below.



    'Paths is a list of only valid Paths found. 
    'If a word prefix or word is not found the path is not
    'added and extending that path is terminated.
    Dim Paths As New Generic.List(Of String)

    'NeighborsOf. The keys are the letters a to p.
    'The value is a string of letters representing neighboring letters.
    'The string of neighboring letters is split and iterated later.
    Dim NeigborsOf As New Generic.Dictionary(Of String, String)

    'BoggleLetters. The keys are mapped to the lettered grid of a to p.
    'The values are what the user inputs on the page.
    Dim BoggleLetters As New Generic.Dictionary(Of String, String)

    'Used to store last postition of path. This will be a letter
    'from a to p.
    Dim LastPositionOfPath As String = ""

    'I found a HashTable was by far faster than a Generic.Dictionary 
    ' - about 10 times faster. This stores prefixes of words and words.
    'I determined 792773 was the number of words and unique prefixes that
    'will be generated from the dictionary file. This is a max number and
    'the final hashtable will not have that many.
    Dim HashTableOfPrefixesAndWords As New Hashtable(792773)

    'Stores words that are found.
    Dim FoundWords As New Generic.List(Of String)

    'Just to validate what the user enters in the grid.
    Dim ErrorFoundWithSubmittedLetters As Boolean = False

    Public Sub BuildAndTestPathsAndFindWords(ByVal ThisPath As String)
        'Word is the word correlating to the ThisPath parameter.
        'This path would be a series of letters from a to p.
        Dim Word As String = ""

        'The path is iterated through and a word based on the actual
        'letters in the Boggle grid is assembled.
        For i As Integer = 0 To ThisPath.Length - 1
            Word += Me.BoggleLetters(ThisPath.Substring(i, 1))
        Next

        'If my hashtable of word prefixes and words doesn't contain this Word
        'Then this isn't a word and any further extension of ThisPath will not
        'yield any words either. So exit sub to terminate exploring this path.
        If Not HashTableOfPrefixesAndWords.ContainsKey(Word) Then Exit Sub

        'The value of my hashtable is a boolean representing if the key if a word (true) or
        'just a prefix (false). If true and at least 3 letters long then yay! word found.
        If HashTableOfPrefixesAndWords(Word) AndAlso Word.Length > 2 Then Me.FoundWords.Add(Word)

        'If my List of Paths doesn't contain ThisPath then add it.
        'Remember only valid paths will make it this far. Paths not found
        'in the HashTableOfPrefixesAndWords cause this sub to exit above.
        If Not Paths.Contains(ThisPath) Then Paths.Add(ThisPath)

        'Examine the last letter of ThisPath. We are looking to extend the path
        'to our neighboring letters if any are still available.
        LastPositionOfPath = ThisPath.Substring(ThisPath.Length - 1, 1)

        'Loop through my list of neighboring letters (representing grid points).
        For Each Neighbor As String In Me.NeigborsOf(LastPositionOfPath).ToCharArray()
            'If I find a neighboring grid point that I haven't already used
            'in ThisPath then extend ThisPath and feed the new path into
            'this recursive function. (see recursive.)
            If Not ThisPath.Contains(Neighbor) Then Me.BuildAndTestPathsAndFindWords(ThisPath & Neighbor)
        Next
    End Sub

    Protected Sub ButtonBoggle_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles ButtonBoggle.Click

        'User has entered the 16 letters and clicked the go button.

        'Set up my Generic.Dictionary of grid points, I'm using letters a to p -
        'not an x,y grid system.  The values are neighboring points.
        NeigborsOf.Add("a", "bfe")
        NeigborsOf.Add("b", "cgfea")
        NeigborsOf.Add("c", "dhgfb")
        NeigborsOf.Add("d", "hgc")
        NeigborsOf.Add("e", "abfji")
        NeigborsOf.Add("f", "abcgkjie")
        NeigborsOf.Add("g", "bcdhlkjf")
        NeigborsOf.Add("h", "cdlkg")
        NeigborsOf.Add("i", "efjnm")
        NeigborsOf.Add("j", "efgkonmi")
        NeigborsOf.Add("k", "fghlponj")
        NeigborsOf.Add("l", "ghpok")
        NeigborsOf.Add("m", "ijn")
        NeigborsOf.Add("n", "ijkom")
        NeigborsOf.Add("o", "jklpn")
        NeigborsOf.Add("p", "klo")

        'Retrieve letters the user entered.
        BoggleLetters.Add("a", Me.TextBox1.Text.ToLower.Trim())
        BoggleLetters.Add("b", Me.TextBox2.Text.ToLower.Trim())
        BoggleLetters.Add("c", Me.TextBox3.Text.ToLower.Trim())
        BoggleLetters.Add("d", Me.TextBox4.Text.ToLower.Trim())
        BoggleLetters.Add("e", Me.TextBox5.Text.ToLower.Trim())
        BoggleLetters.Add("f", Me.TextBox6.Text.ToLower.Trim())
        BoggleLetters.Add("g", Me.TextBox7.Text.ToLower.Trim())
        BoggleLetters.Add("h", Me.TextBox8.Text.ToLower.Trim())
        BoggleLetters.Add("i", Me.TextBox9.Text.ToLower.Trim())
        BoggleLetters.Add("j", Me.TextBox10.Text.ToLower.Trim())
        BoggleLetters.Add("k", Me.TextBox11.Text.ToLower.Trim())
        BoggleLetters.Add("l", Me.TextBox12.Text.ToLower.Trim())
        BoggleLetters.Add("m", Me.TextBox13.Text.ToLower.Trim())
        BoggleLetters.Add("n", Me.TextBox14.Text.ToLower.Trim())
        BoggleLetters.Add("o", Me.TextBox15.Text.ToLower.Trim())
        BoggleLetters.Add("p", Me.TextBox16.Text.ToLower.Trim())

        'Validate user entered something with a length of 1 for all 16 textboxes.
        For Each S As String In BoggleLetters.Keys
            If BoggleLetters(S).Length <> 1 Then
                ErrorFoundWithSubmittedLetters = True
                Exit For
            End If
        Next

        'If input is not valid then...
        If ErrorFoundWithSubmittedLetters Then
            'Present error message.
        Else
            'Else assume we have 16 letters to work with and start finding words.
            Dim SB As New StringBuilder

            Dim Time As String = String.Format("{0}:{1}:{2}:{3}", Date.Now.Hour.ToString(), Date.Now.Minute.ToString(), Date.Now.Second.ToString(), Date.Now.Millisecond.ToString())

            Dim NumOfLetters As Integer = 0
            Dim Word As String = ""
            Dim TempWord As String = ""
            Dim Letter As String = ""
            Dim fr As StreamReader = Nothing
            fr = New System.IO.StreamReader(HttpContext.Current.Request.MapPath("~/boggle/dic.txt"))

            'First fill my hashtable with word prefixes and words.
            'HashTable(PrefixOrWordString, BooleanTrueIfWordFalseIfPrefix)
            While fr.Peek <> -1
                Word = fr.ReadLine.Trim()
                TempWord = ""
                For i As Integer = 0 To Word.Length - 1
                    Letter = Word.Substring(i, 1)
                    'This optimization helped quite a bit. Words in the dictionary that begin
                    'with letters that the user did not enter in the grid shouldn't go in my hashtable.
                    '
                    'I realize most of the solutions went with a Trie. I'd never heard of that before,
                    'which is one of the neat things about SO, seeing how others approach challenges
                    'and learning some best practices.
                    '
                    'However, I didn't code a Trie in my solution. I just have a hashtable with 
                    'all words in the dicitonary file and all possible prefixes for those words.
                    'A Trie might be faster but I'm not coding it now. I'm getting good times with this.
                    If i = 0 AndAlso Not BoggleLetters.ContainsValue(Letter) Then Continue While
                    TempWord += Letter
                    If Not HashTableOfPrefixesAndWords.ContainsKey(TempWord) Then
                        HashTableOfPrefixesAndWords.Add(TempWord, TempWord = Word)
                    End If
                Next
            End While

            SB.Append("Number of Word Prefixes and Words in Hashtable: " & HashTableOfPrefixesAndWords.Count.ToString())
            SB.Append("<br />")

            SB.Append("Loading Dictionary: " & Time & " - " & String.Format("{0}:{1}:{2}:{3}", Date.Now.Hour.ToString(), Date.Now.Minute.ToString(), Date.Now.Second.ToString(), Date.Now.Millisecond.ToString()))
            SB.Append("<br />")

            Time = String.Format("{0}:{1}:{2}:{3}", Date.Now.Hour.ToString(), Date.Now.Minute.ToString(), Date.Now.Second.ToString(), Date.Now.Millisecond.ToString())

            'This starts a path at each point on the grid an builds a path until 
            'the string of letters correlating to the path is not found in the hashtable
            'of word prefixes and words.
            Me.BuildAndTestPathsAndFindWords("a")
            Me.BuildAndTestPathsAndFindWords("b")
            Me.BuildAndTestPathsAndFindWords("c")
            Me.BuildAndTestPathsAndFindWords("d")
            Me.BuildAndTestPathsAndFindWords("e")
            Me.BuildAndTestPathsAndFindWords("f")
            Me.BuildAndTestPathsAndFindWords("g")
            Me.BuildAndTestPathsAndFindWords("h")
            Me.BuildAndTestPathsAndFindWords("i")
            Me.BuildAndTestPathsAndFindWords("j")
            Me.BuildAndTestPathsAndFindWords("k")
            Me.BuildAndTestPathsAndFindWords("l")
            Me.BuildAndTestPathsAndFindWords("m")
            Me.BuildAndTestPathsAndFindWords("n")
            Me.BuildAndTestPathsAndFindWords("o")
            Me.BuildAndTestPathsAndFindWords("p")

            SB.Append("Finding Words: " & Time & " - " & String.Format("{0}:{1}:{2}:{3}", Date.Now.Hour.ToString(), Date.Now.Minute.ToString(), Date.Now.Second.ToString(), Date.Now.Millisecond.ToString()))
            SB.Append("<br />")

            SB.Append("Num of words found: " & FoundWords.Count.ToString())
            SB.Append("<br />")
            SB.Append("<br />")

            FoundWords.Sort()
            SB.Append(String.Join("<br />", FoundWords.ToArray()))

            'Output results.
            Me.LiteralBoggleResults.Text = SB.ToString()
            Me.PanelBoggleResults.Visible = True

        End If

    End Sub

End Class

我在Java上的尝试。读取文件和构建trie大约需要2秒，解决谜题大约需要50毫秒。我用了问题中链接的字典(里面有几个我不知道在英语中存在的单词，比如fae, ima)

0 [main] INFO gineer.bogglesolver.util.Util  - Reading the dictionary
2234 [main] INFO gineer.bogglesolver.util.Util  - Finish reading the dictionary
2234 [main] INFO gineer.bogglesolver.Solver  - Found: FAM
2234 [main] INFO gineer.bogglesolver.Solver  - Found: FAME
2234 [main] INFO gineer.bogglesolver.Solver  - Found: FAMBLE
2234 [main] INFO gineer.bogglesolver.Solver  - Found: FAE
2234 [main] INFO gineer.bogglesolver.Solver  - Found: IMA
2234 [main] INFO gineer.bogglesolver.Solver  - Found: ELI
2234 [main] INFO gineer.bogglesolver.Solver  - Found: ELM
2234 [main] INFO gineer.bogglesolver.Solver  - Found: ELB
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AXIL
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AXILE
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AXLE
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AMI
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AMIL
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AMLI
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AME
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AMBLE
2234 [main] INFO gineer.bogglesolver.Solver  - Found: AMBO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AES
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWEST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MIX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MIL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MILE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MILO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MAX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MAE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MAW
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MEW
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MEWL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MES
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MESA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: MWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMAX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIME
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMES
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMB
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMBO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LIMBU
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LEI
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LEO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LOB
2250 [main] INFO gineer.bogglesolver.Solver  - Found: LOX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: OIME
2250 [main] INFO gineer.bogglesolver.Solver  - Found: OIL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: OLE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: OLM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: EMIL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: EMBOLE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: EMBOX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: EAST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAF
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAME
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAMBLE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WEA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WEAM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WEM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WEA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WES
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WEST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAS
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WASE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: WAST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: BLEO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: BLO
2250 [main] INFO gineer.bogglesolver.Solver  - Found: BOIL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: BOLE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: BUT
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AES
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWL
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AWEST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: ASE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: ASEM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: AST
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEAX
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEAM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEMI
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEMBLE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEW
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SEA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SWAM
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SWAMI
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SAW
2250 [main] INFO gineer.bogglesolver.Solver  - Found: SAWT
2250 [main] INFO gineer.bogglesolver.Solver  - Found: STU
2250 [main] INFO gineer.bogglesolver.Solver  - Found: STUB
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TWAE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TWA
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TWAE
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TWAS
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TUB
2250 [main] INFO gineer.bogglesolver.Solver  - Found: TUX

源代码由6个类组成。我将把它们贴在下面(如果这不是StackOverflow的正确做法，请告诉我)。

gineer.bogglesolver.Main

package gineer.bogglesolver;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;

public class Main
{
    private final static Logger logger = Logger.getLogger(Main.class);

    public static void main(String[] args)
    {
        BasicConfigurator.configure();

        Solver solver = new Solver(4,
                        "FXIE" +
                        "AMLO" +
                        "EWBX" +
                        "ASTU");
        solver.solve();

    }
}

gineer.bogglesolver.Solver

package gineer.bogglesolver;

import gineer.bogglesolver.trie.Trie;
import gineer.bogglesolver.util.Constants;
import gineer.bogglesolver.util.Util;
import org.apache.log4j.Logger;

public class Solver
{
    private char[] puzzle;
    private int maxSize;

    private boolean[] used;
    private StringBuilder stringSoFar;

    private boolean[][] matrix;
    private Trie trie;

    private final static Logger logger = Logger.getLogger(Solver.class);

    public Solver(int size, String puzzle)
    {
        trie = Util.getTrie(size);
        matrix = Util.connectivityMatrix(size);

        maxSize = size * size;
        stringSoFar = new StringBuilder(maxSize);
        used = new boolean[maxSize];

        if (puzzle.length() == maxSize)
        {
            this.puzzle = puzzle.toCharArray();
        }
        else
        {
            logger.error("The puzzle size does not match the size specified: " + puzzle.length());
            this.puzzle = puzzle.substring(0, maxSize).toCharArray();
        }
    }

    public void solve()
    {
        for (int i = 0; i < maxSize; i++)
        {
            traverseAt(i);
        }
    }

    private void traverseAt(int origin)
    {
        stringSoFar.append(puzzle[origin]);
        used[origin] = true;

        //Check if we have a valid word
        if ((stringSoFar.length() >= Constants.MINIMUM_WORD_LENGTH) && (trie.containKey(stringSoFar.toString())))
        {
            logger.info("Found: " + stringSoFar.toString());
        }

        //Find where to go next
        for (int destination = 0; destination < maxSize; destination++)
        {
            if (matrix[origin][destination] && !used[destination] && trie.containPrefix(stringSoFar.toString() + puzzle[destination]))
            {
                traverseAt(destination);
            }
        }

        used[origin] = false;
        stringSoFar.deleteCharAt(stringSoFar.length() - 1);
    }

}

gineer.bogglesolver.trie.Node

package gineer.bogglesolver.trie;

import gineer.bogglesolver.util.Constants;

class Node
{
    Node[] children;
    boolean isKey;

    public Node()
    {
        isKey = false;
        children = new Node[Constants.NUMBER_LETTERS_IN_ALPHABET];
    }

    public Node(boolean key)
    {
        isKey = key;
        children = new Node[Constants.NUMBER_LETTERS_IN_ALPHABET];
    }

    /**
     Method to insert a string to Node and its children

     @param key the string to insert (the string is assumed to be uppercase)
     @return true if the node or one of its children is changed, false otherwise
     */
    public boolean insert(String key)
    {
        //If the key is empty, this node is a key
        if (key.length() == 0)
        {
            if (isKey)
                return false;
            else
            {
                isKey = true;
                return true;
            }
        }
        else
        {//otherwise, insert in one of its child

            int childNodePosition = key.charAt(0) - Constants.LETTER_A;
            if (children[childNodePosition] == null)
            {
                children[childNodePosition] = new Node();
                children[childNodePosition].insert(key.substring(1));
                return true;
            }
            else
            {
                return children[childNodePosition].insert(key.substring(1));
            }
        }
    }

    /**
     Returns whether key is a valid prefix for certain key in this trie.
     For example: if key "hello" is in this trie, tests with all prefixes "hel", "hell", "hello" return true

     @param prefix the prefix to check
     @return true if the prefix is valid, false otherwise
     */
    public boolean containPrefix(String prefix)
    {
        //If the prefix is empty, return true
        if (prefix.length() == 0)
        {
            return true;
        }
        else
        {//otherwise, check in one of its child
            int childNodePosition = prefix.charAt(0) - Constants.LETTER_A;
            return children[childNodePosition] != null && children[childNodePosition].containPrefix(prefix.substring(1));
        }
    }

    /**
     Returns whether key is a valid key in this trie.
     For example: if key "hello" is in this trie, tests with all prefixes "hel", "hell" return false

     @param key the key to check
     @return true if the key is valid, false otherwise
     */
    public boolean containKey(String key)
    {
        //If the prefix is empty, return true
        if (key.length() == 0)
        {
            return isKey;
        }
        else
        {//otherwise, check in one of its child
            int childNodePosition = key.charAt(0) - Constants.LETTER_A;
            return children[childNodePosition] != null && children[childNodePosition].containKey(key.substring(1));
        }
    }

    public boolean isKey()
    {
        return isKey;
    }

    public void setKey(boolean key)
    {
        isKey = key;
    }
}

gineer.bogglesolver.trie.Trie

package gineer.bogglesolver.trie;

public class Trie
{
    Node root;

    public Trie()
    {
        this.root = new Node();
    }

    /**
     Method to insert a string to Node and its children

     @param key the string to insert (the string is assumed to be uppercase)
     @return true if the node or one of its children is changed, false otherwise
     */
    public boolean insert(String key)
    {
        return root.insert(key.toUpperCase());
    }

    /**
     Returns whether key is a valid prefix for certain key in this trie.
     For example: if key "hello" is in this trie, tests with all prefixes "hel", "hell", "hello" return true

     @param prefix the prefix to check
     @return true if the prefix is valid, false otherwise
     */
    public boolean containPrefix(String prefix)
    {
        return root.containPrefix(prefix.toUpperCase());
    }

    /**
     Returns whether key is a valid key in this trie.
     For example: if key "hello" is in this trie, tests with all prefixes "hel", "hell" return false

     @param key the key to check
     @return true if the key is valid, false otherwise
     */
    public boolean containKey(String key)
    {
        return root.containKey(key.toUpperCase());
    }


}

gineer.bogglesolver.util.Constants

package gineer.bogglesolver.util;

public class Constants
{

    public static final int NUMBER_LETTERS_IN_ALPHABET = 26;
    public static final char LETTER_A = 'A';
    public static final int MINIMUM_WORD_LENGTH = 3;
    public static final int DEFAULT_PUZZLE_SIZE = 4;
}

gineer.bogglesolver.util.Util

package gineer.bogglesolver.util;

import gineer.bogglesolver.trie.Trie;
import org.apache.log4j.Logger;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Util
{
    private final static Logger logger = Logger.getLogger(Util.class);
    private static Trie trie;
    private static int size = Constants.DEFAULT_PUZZLE_SIZE;

    /**
     Returns the trie built from the dictionary.  The size is used to eliminate words that are too long.

     @param size the size of puzzle.  The maximum lenght of words in the returned trie is (size * size)
     @return the trie that can be used for puzzle of that size
     */
    public static Trie getTrie(int size)
    {
        if ((trie != null) && size == Util.size)
            return trie;

        trie = new Trie();
        Util.size = size;

        logger.info("Reading the dictionary");
        final File file = new File("dictionary.txt");
        try
        {
            Scanner scanner = new Scanner(file);
            final int maxSize = size * size;
            while (scanner.hasNext())
            {
                String line = scanner.nextLine().replaceAll("[^\\p{Alpha}]", "");

                if (line.length() <= maxSize)
                    trie.insert(line);
            }
        }
        catch (FileNotFoundException e)
        {
            logger.error("Cannot open file", e);
        }

        logger.info("Finish reading the dictionary");
        return trie;
    }

    static boolean[] connectivityRow(int x, int y, int size)
    {
        boolean[] squares = new boolean[size * size];
        for (int offsetX = -1; offsetX <= 1; offsetX++)
        {
            for (int offsetY = -1; offsetY <= 1; offsetY++)
            {
                final int calX = x + offsetX;
                final int calY = y + offsetY;
                if ((calX >= 0) && (calX < size) && (calY >= 0) && (calY < size))
                    squares[calY * size + calX] = true;
            }
        }

        squares[y * size + x] = false;//the current x, y is false

        return squares;
    }

    /**
     Returns the matrix of connectivity between two points.  Point i can go to point j iff matrix[i][j] is true
     Square (x, y) is equivalent to point (size * y + x).  For example, square (1,1) is point 5 in a puzzle of size 4

     @param size the size of the puzzle
     @return the connectivity matrix
     */
    public static boolean[][] connectivityMatrix(int size)
    {
        boolean[][] matrix = new boolean[size * size][];
        for (int x = 0; x < size; x++)
        {
            for (int y = 0; y < size; y++)
            {
                matrix[y * size + x] = connectivityRow(x, y, size);
            }
        }
        return matrix;
    }
}

我意识到这个问题的时间来了又去了，但由于我自己正在研究一个求解器，并在谷歌搜索时偶然发现了这个，我想我应该发布一个参考，因为它似乎与其他一些问题有点不同。

我选择在游戏棋盘上使用平面数组，并从棋盘上的每个字母进行递归搜索，从有效邻居遍历到有效邻居，如果索引中的有效前缀是当前字母列表，则扩展搜索。而遍历当前单词的概念是进入板的索引列表，而不是组成单词的字母。在检查索引时，将索引转换为字母并完成检查。

索引是一个蛮力字典，有点像trie，但允许对索引进行python查询。如果单词'cat'和'cater'在列表中，你会在字典中看到:

   d = { 'c': ['cat','cater'],
     'ca': ['cat','cater'],
     'cat': ['cat','cater'],
     'cate': ['cater'],
     'cater': ['cater'],
   }

因此，如果current_word是'ca'，您就知道它是一个有效的前缀，因为'ca'在d中返回True(因此继续遍历板)。如果current_word是'cat'，那么你知道它是一个有效的单词，因为它是一个有效的前缀，并且d['cat']中的'cat'也返回True。

如果感觉这允许一些可读的代码，似乎不是太慢。像其他人一样，这个系统的费用是读取/构建索引。解这个板子相当麻烦。

代码在http://gist.github.com/268079。它是故意垂直和幼稚的，有很多明确的有效性检查，因为我想理解问题，而不是用一堆魔法或晦涩难懂的东西把它弄得乱七八糟。

令人惊讶的是，没有人尝试使用PHP版本。

这是John Fouhy的Python解决方案的PHP版本。

虽然我从其他人的答案中得到了一些建议，但这主要是抄袭约翰的。

$boggle = "fxie
           amlo
           ewbx
           astu";

$alphabet = str_split(str_replace(array("\n", " ", "\r"), "", strtolower($boggle)));
$rows = array_map('trim', explode("\n", $boggle));
$dictionary = file("C:/dict.txt");
$prefixes = array(''=>'');
$words = array();
$regex = '/[' . implode('', $alphabet) . ']{3,}$/S';
foreach($dictionary as $k=>$value) {
    $value = trim(strtolower($value));
    $length = strlen($value);
    if(preg_match($regex, $value)) {
        for($x = 0; $x < $length; $x++) {
            $letter = substr($value, 0, $x+1);
            if($letter == $value) {
                $words[$value] = 1;
            } else {
                $prefixes[$letter] = 1;
            }
        }
    }
}

$graph = array();
$chardict = array();
$positions = array();
$c = count($rows);
for($i = 0; $i < $c; $i++) {
    $l = strlen($rows[$i]);
    for($j = 0; $j < $l; $j++) {
        $chardict[$i.','.$j] = $rows[$i][$j];
        $children = array();
        $pos = array(-1,0,1);
        foreach($pos as $z) {
            $xCoord = $z + $i;
            if($xCoord < 0 || $xCoord >= count($rows)) {
                continue;
            }
            $len = strlen($rows[0]);
            foreach($pos as $w) {
                $yCoord = $j + $w;
                if(($yCoord < 0 || $yCoord >= $len) || ($z == 0 && $w == 0)) {
                    continue;
                }
                $children[] = array($xCoord, $yCoord);
            }
        }
        $graph['None'][] = array($i, $j);
        $graph[$i.','.$j] = $children;
    }
}

function to_word($chardict, $prefix) {
    $word = array();
    foreach($prefix as $v) {
        $word[] = $chardict[$v[0].','.$v[1]];
    }
    return implode("", $word);
}

function find_words($graph, $chardict, $position, $prefix, $prefixes, &$results, $words) {
    $word = to_word($chardict, $prefix);
    if(!isset($prefixes[$word])) return false;

    if(isset($words[$word])) {
        $results[] = $word;
    }

    foreach($graph[$position] as $child) {
        if(!in_array($child, $prefix)) {
            $newprefix = $prefix;
            $newprefix[] = $child;
            find_words($graph, $chardict, $child[0].','.$child[1], $newprefix, $prefixes, $results, $words);
        }
    }
}

$solution = array();
find_words($graph, $chardict, 'None', array(), $prefixes, $solution);
print_r($solution);

如果你想尝试的话，这里有一个实时链接。虽然在我的本地机器上需要大约2秒，但在我的web服务器上需要大约5秒。无论哪种情况，它都不是很快。尽管如此，它还是很可怕，所以我可以想象时间可以大大缩短。任何关于如何实现这一目标的建议都将不胜感激。PHP缺少元组，这使得坐标处理起来很奇怪，而且我无法理解到底发生了什么，这对我一点帮助都没有。

编辑:一些修复使它在本地少于1秒。

这是我想出的解决填字游戏的办法。我想这是最“python”的做事方式:

from itertools import combinations
from itertools import izip
from math import fabs

def isAllowedStep(current,step,length,doubleLength):
            # for step == length -1 not to be 0 => trivial solutions are not allowed
    return length > 1 and \
           current + step < doubleLength and current - step > 0 and \
           ( step == 1 or step == -1 or step <= length+1 or step >= length - 1)

def getPairwiseList(someList):
    iterableList = iter(someList)
    return izip(iterableList, iterableList)

def isCombinationAllowed(combination,length,doubleLength):

    for (first,second) in  getPairwiseList(combination):
        _, firstCoordinate = first
        _, secondCoordinate = second
        if not isAllowedStep(firstCoordinate, fabs(secondCoordinate-firstCoordinate),length,doubleLength):
            return False
    return True

def extractSolution(combinations):
    return ["".join([x[0] for x in combinationTuple]) for combinationTuple in combinations]


length = 4
text = tuple("".join("fxie amlo ewbx astu".split()))
textIndices = tuple(range(len(text)))
coordinates = zip(text,textIndices)

validCombinations = [combination for combination in combinations(coordinates,length) if isCombinationAllowed(combination,length,length*length)]
solution = extractSolution(validCombinations)

我善意地建议你不要将这部分用于所有可能的匹配，但它实际上提供了一种检查你生成的单词是否真的构成有效单词的可能性:

import mechanize
def checkWord(word):
    url = "https://en.oxforddictionaries.com/search?filter=dictionary&query="+word
    br = mechanize.Browser()
    br.set_handle_robots(False)
    response = br.open(url)
    text = response.read()
    return "no exact matches"  not in text.lower()

print [valid for valid in solution[:10] if checkWord(valid)]

我花了3个月的时间致力于解决10个最佳点密集的5x5 Boggle板问题。

这个问题现在已经解决了，并在5个网页上进行了全面披露。有问题请联系我。

该棋盘分析算法使用显式堆栈，通过具有直接子信息的有向无环词图伪递归遍历棋盘方格，并使用时间戳跟踪机制。这很可能是世界上最先进的词汇数据结构。

该方案在四核上每秒评估大约10,000块非常好的电路板。(9500 +分)

父网页:

DeepSearch.c - http://www.pathcom.com/~vadco/deep.html

组件网页:

最佳记分牌- http://www.pathcom.com/~vadco/binary.html

高级词汇结构- http://www.pathcom.com/~vadco/adtdawg.html

板分析算法- http://www.pathcom.com/~vadco/guns.html

并行批处理- http://www.pathcom.com/~vadco/parallel.html

- 只有追求最好的人才会对这本全面的著作感兴趣。