从 trie 中按字母顺序打印所有单词

Question

我对尝试很陌生。我在网上找到了一些解决方案，但尝试以完全不同的方式定义。我需要这种类型的特里的解决方案。

我需要的是按字母顺序打印 trie 中所有单词的功能。如您所见，插入和搜索功能已完成。这里有2个头文件，是主代码所必需的。

EntryType.h

#include <iostream>
using namespace std;

const int MAXLENGTH = 10;
class EntryType
{
public:
    EntryType();
    EntryType(char * key);
    EntryType(EntryType & entry);
    ~EntryType();
    bool operator== (const EntryType& item) const;
    bool operator!= (const EntryType& item) const;
    friend istream& operator>> (istream& is, EntryType& item);
    friend ostream& operator<< (ostream& os, EntryType item);
    void EntryKey(char word[]);
    void PrintWord();

private:
    char entryKey[MAXLENGTH];
};

ostream& operator<< (ostream& os, EntryType item)
{
    os << item.entryKey;
    return os;
}

EntryType::EntryType()
{
    // empty instance constructor
}
EntryType::~EntryType()
{
    // destructor
}

void EntryType::EntryKey(char word[])
{
    for (int i = 0; i < 10; i++)
    {
        entryKey[i] = word[i];
    }
}

void EntryType::PrintWord()
{
    cout << entryKey << endl;
}

TrieType.h

#include <iostream>
#include <string>
#include "EntryType.h"


const int LETTERS = 26;
typedef char Key[MAXLENGTH];
struct Trienode
{
    Trienode *branch[LETTERS];
    EntryType *ref;
};

class TrieType
{

private:
    Trienode * root;

public:
    TrieType();
    ~TrieType();
    TrieType(TrieType &originalTree);
    void operator=(TrieType & originalTree);
    void MakeEmpty();
    void InsertTrie(Key newkey, EntryType *newentry);
    EntryType *  TrieSearch(Key target);
    bool DeleteTrie(Key delkey);
    void PrintTrie();
};

TrieType::TrieType()
{
    root = NULL;
}


TrieType::~TrieType()
{
    // destructor
}
TrieType::TrieType(TrieType &originalTree)
{
    // constructor
}

EntryType *TrieType::TrieSearch(Key target)
{
    int i;
    Trienode * current = root;
    for (i = 0; i < MAXLENGTH && current; i++)
    if (target[i] == '\0')
        break;
    else
        current =
        current->branch[target[i] - 'a'];
    if (!current)
        return NULL;
    else
    if (!current->ref)
        return NULL;

    return current->ref;
}


Trienode *CreateNode()
{
    int ch;
    Trienode *newnode = new Trienode;
    for (ch = 0; ch < LETTERS; ch++)
        newnode->branch[ch] = NULL;

    newnode->ref = NULL;

    return newnode;
}

void TrieType::InsertTrie(Key newkey, EntryType *newentry)
{
    int i;
    Trienode *current;
    if (!root)
        root = CreateNode();
    current = root;
    for (i = 0; i < MAXLENGTH; i++)
    if (newkey[i] == '\0')
        break;
    else
    {
        if (!current->branch[newkey[i] - 'a'])
            current->branch[newkey[i] - 'a'] = CreateNode();
        current = current->branch[newkey[i] - 'a'];
    }
    if (current->ref != NULL)
        cout << "\nTried to insert a duplicate key." << endl;
    else
        current->ref = newentry;
}

Answer 1

我知道在我发布这个问题后已经快一年了，但我终于找到了解决方案。在这里……

TrieType.h

#include <iostream>
#include <string>
//added:###############################################
#include<algorithm>
#include<vector>
//#####################################################
#include "EntryType.h"


const int LETTERS = 26;
typedef char Key[MAXLENGTH];
struct Trienode
{
    Trienode *branch[LETTERS];
    EntryType *ref;
};

class TrieType
{

private:
    Trienode * root;

public:
    TrieType();
    ~TrieType();
    TrieType(TrieType &originalTree);
    void operator=(TrieType & originalTree);
    void MakeEmpty();
    void InsertTrie(Key newkey, EntryType *newentry);
    EntryType *  TrieSearch(Key target);
    bool DeleteTrie(Key delkey);
    void PrintTrie();
};

TrieType::TrieType()
{
    root = NULL;
}


TrieType::~TrieType()
{
    // destructor
}
TrieType::TrieType(TrieType &originalTree)
{
    // constructor
}

EntryType *TrieType::TrieSearch(Key target)
{
    int i;
    Trienode * current = root;
    for (i = 0; i < MAXLENGTH && current; i++)
    if (target[i] == '\0')
        break;
    else
        current =
        current->branch[target[i] - 'a'];
    if (!current)
        return NULL;
    else
    if (!current->ref)
        return NULL;

    return current->ref;
}


Trienode *CreateNode()
{
    int ch;
    Trienode *newnode = new Trienode;
    for (ch = 0; ch < LETTERS; ch++)
        newnode->branch[ch] = NULL;

    newnode->ref = NULL;

    return newnode;
}

void TrieType::InsertTrie(Key newkey, EntryType *newentry)
{
    int i;
    Trienode *current;
    if (!root)
        root = CreateNode();
    current = root;
    for (i = 0; i < MAXLENGTH; i++)
    if (newkey[i] == '\0')
        break;
    else
    {
        if (!current->branch[newkey[i] - 'a'])
            current->branch[newkey[i] - 'a'] = CreateNode();
        current = current->branch[newkey[i] - 'a'];
    }
    if (current->ref != NULL)
        cout << "\nTried to insert a duplicate key." << endl;
    else
        current->ref = newentry;
}

//Added:################################################################33
void Traverse(Trienode *current,vector<string> v)
{
    if(current->ref != NULL)
    {
        //add the same prevous word as the new word, will remove char by char while moving upwards the tree to get into ne branch
        v.push_back(v[v.size()-1]);
        return;
    }
    for (int i = 0; i < LETTERS; i++)
    {
        if(current->branch[i] != NULL)
        {
            //each level contains childs as much as english letters in the same order(if any is null then the letter in this position is not used)
            v[v.size()-1] += (char)((int)'a' + i);
            current = current->branch[i];
            Traverse(current, v);
            //remove any additional chars from previous word to get new word from continuing from old word
            v[v.size()-1] =  v[v.size()-1].substr(0, v[v.size()-1].size()-1);
        }
    }
}

void TrieType::PrintTrie()
{
    //temporarly saves the list of unsorted words
    vector<string> wordList;
    wordList.push_back("");
    Traverse(root, wordList );
    sort(wordList.begin(), wordList.end());

    for (int i = 0; i < wordList.size(); i++)
    {
        cout<<"Word "<<i<<": "<<wordList[i]<<endl;
    }
}

EntryType.h

#include <iostream>
using namespace std;

const int MAXLENGTH = 10;
class EntryType
{
public:
    EntryType();
    EntryType(char * key);
    EntryType(EntryType & entry);
    ~EntryType();
    bool operator== (const EntryType& item) const;
    bool operator!= (const EntryType& item) const;
    friend istream& operator>> (istream& is, EntryType& item);
    friend ostream& operator<< (ostream& os, EntryType item);
    void EntryKey(char word[]);
    void PrintWord();

private:
    char entryKey[MAXLENGTH];
};

ostream& operator<< (ostream& os, EntryType item)
{
    os << item.entryKey;
    return os;
}

EntryType::EntryType()
{
    // empty instance constructor
}
EntryType::~EntryType()
{
    // destructor
}

void EntryType::EntryKey(char word[])
{
    for (int i = 0; i < 10; i++)
    {
        entryKey[i] = word[i];
    }
}

void EntryType::PrintWord()
{
    cout << entryKey << endl;
}

main.cpp

#include <iostream>
#include <string>
#include "TrieType.h"

using namespace std;

TrieType t;
char newelem[10];

void insert(TrieType & trie)
{
    Key word;
    cout << "Enter the word you would like to insert into trie: " << endl;
    cin >> word;

    EntryType* newEntry = new EntryType;
    newEntry->EntryKey(word);

    trie.InsertTrie(word, newEntry);
    cout << "Word " << word <<" has been inserted into trie!"<< endl;
}

void getAllWords(TrieType & trie)
{
    cout << "All words in trie are: " << endl;

    EntryType* newEntry = new EntryType;
    //newEntry->PrintWord();
    trie.PrintTrie();
}

int main()
{
    int i;

    do
    {
        cout << "\nMENU\n-------------------- " << endl;
        cout << "1. Insert into a Trie" << endl;
        cout << "2. Search a Trie" << endl;
        cout << "3. Print Words Alphabetically" << endl;
        cout << "4. Exit" << endl;
        cout << "Please enter an integer value: ";
        cin >> i;
        switch (i)
        {
        case 1: 
            insert(t);
            break;
        case 2: 
            cout << "Enter string to search trie:";
            cin >> newelem;
            if (t.TrieSearch(newelem) != NULL)
            {
                cout << "String " << newelem << " is member of trie!" << endl;
            }
            else
            {
                cout << "String " << newelem << " is NOT member of trie!" << endl;
            }
            break;
        case 3:
            cout << "TO BE DONE!!!" << endl;
            t.PrintTrie();
            break;
        case 4:
            cout << "Exiting program..." << endl;
            break;
        default:
            cout << "Wrong input" << endl;
            break;
        }

    } while (i != 4);
    return 0;
}

我希望这将帮助某人弄清楚如何处理这些类型的树