Trie树_字典树(字符串排序)简介及实现

const int branchNum = 26; //声明常量
int i;
 
struct Trie_node
{
       boolisStr;                //记录此处是否构成一个串。
       Trie_node*next[branchNum];//指向各个子树的指针,下标0-25代表26字符
       Trie_node():isStr(false)
       {
              memset(next,NULL,sizeof(next));
       }
};
 
class Trie
{
 public:
     Trie();
     voidinsert(const char* word);
     boolsearch(char* word);
     voiddeleteTrie(Trie_node *root);
       // voidprintTrie(Trie_node *root);   //new add
 
private:
    Trie_node* root;
 };
 
Trie::Trie()
{
     root =new Trie_node();
}
 
void Trie::insert(const char* word)
 {
    Trie_node*location = root;
   while(*word)
     {
       if(location->next[*word-'a'] == NULL)//不存在则建立
         {
           Trie_node *tmp = new Trie_node();
           location->next[*word-'a'] = tmp;
        }  
       location = location->next[*word-'a']; //每一步，相当于有一个新串经过，指针要向下移动
       word++;
    }
   location->isStr = true; //到达尾部,标记一个串
 }
 
bool Trie::search(char *word)
{
       Trie_node*location = root;
       while(*word&& location)
       {
              location= location->next[*word-'a'];
              word++;
       }
       return(location!=NULL && location->isStr);
 }
 
void Trie::deleteTrie(Trie_node *root)
{
       for(i =0; i < branchNum; i++)
       {
              if(root->next[i]!= NULL)
              {
                     deleteTrie(root->next[i]);
              }
       }
       deleteroot;
}
 
void main() //简单测试
{
       Trie t;
       t.insert("a");       
       t.insert("abandon");
 
       char * c= "abandoned";
       t.insert(c);
       t.insert("abashed");
 
       if(t.search("abashed"))
       {
          printf("true\n");  
       }
}

#include <iostream>
#include <string.h>
using namespace std;
#define NUM 26
class Node
{
public:
    int count; //记录该处字符串个数
    Node* char_arr[NUM];  //分支
    char* current_str;   //记录到达此处的路径上的所有字母组成的字符串
    Node();
};
class Trie
{
public:
    Node* root;
    Trie();
    void insert(char* str);
    void output(Node* &node, char** str, int& count);
};
//程序未考虑delete动态内存
int main()
{
    char** str = new char*[12];
    str[0] = "zbdfasd";
    str[1] = "zbcfd";
    str[2] = "zbcdfdasfasf";
    str[3] = "abcdaf";
    str[4] = "defdasfa";
    str[5] = "fedfasfd";
    str[6] = "dfdfsa";
    str[7] = "dadfd";
    str[8] = "dfdfasf";
    str[9] = "abcfdfa";
    str[10] = "fbcdfd";
    str[11] = "abcdaf";
    //建立trie树
    Trie* trie = new Trie();
    for(int i = 0; i < 12; i++)
        trie->insert(str[i]);
    int count = 0;
    trie->output(trie->root, str, count);
    for(int i = 0; i < 12; i++)
        cout<<str[i]<<endl;
    return 0;
}
Node::Node()
{
    count = 0;
    for(int i = 0; i < NUM; i++)
        char_arr[i] = NULL;
    current_str = new char[100];
    current_str[0] = '\0';
}
Trie::Trie()
{
    root = new Node();
}
void Trie::insert(char* str)
{
    int i = 0;
    Node* parent = root;
    //将str[i]到trie树中
    while(str[i] != '\0')
    {
        //如果包含str[i]的分支存在，则新建此分支
        if(parent->char_arr[str[i] - 'a'] == NULL)
        {
            parent->char_arr[str[i] - 'a'] = new Node();
            //将父节点中的字符串添加到当前节点的字符串中
            strcat(parent->char_arr[str[i] - 'a']->current_str, parent->current_str);
            char str_tmp[2];
            str_tmp[0] = str[i];
            str_tmp[1] = '\0';
            //将str[i]添加到当前节点的字符串中
            strcat(parent->char_arr[str[i] - 'a']->current_str, str_tmp);
            parent = parent->char_arr[str[i] - 'a'];
        }
        else
        {
            parent = parent->char_arr[str[i] - 'a'];
        }
        i++;
    }
    parent->count++;
}
//采用前序遍历
void Trie::output(Node* &node, char** str, int& count)
{
    if(node != NULL)
    {
        if(node->count != 0)
        {
            for(int i = 0; i < node->count; i++)
                str[count++] = node->current_str;
        }
        for(int i = 0; i < NUM; i++)
        {
            output(node->char_arr[i], str, count);
        }
    }
}