c_cpp Trie数据结构

Posted 2021-05-14

#pragma once  
  
#include <stdio.h>    
#include "stdlib.h"  
#include <iostream>  
#include <string.h>  
using namespace std;  
  
//宏定义      
#define TRUE   1      
#define FALSE   0     
#define NULL 0  
#define OK    1      
#define ERROR   0    
#define INFEASIBLE -1      
#define OVERFLOW -2    
  
const int num_chars = 26;  
class Trie {  
public:  
    Trie();  
    Trie(Trie& tr);  
    virtual ~Trie();  
    int trie_search(const char* word, char* entry ) const;  
    int insert(const char* word, const char* entry);  
    int remove(const char* word, char* entry);  
protected:  
     struct Trie_node{  
           char* data; //若不为空，表示从root到此结点构成一个单词   
           Trie_node* branch[num_chars]; //分支   
           Trie_node(); //构造函数   
     };  
       
     Trie_node* root; //根结点(指针)   
  
}; 

#include "trie.h"

Trie::Trie_node::Trie_node() {  
    data = NULL;      
    for (int i=0; i<num_chars; ++i)   
        branch[i] = NULL;  
}  

Trie::Trie():root(NULL) {}  

Trie::~Trie(){}  

int Trie::trie_search(const char* word, char* entry ) const {    
    int position = 0;  //层数   
    char char_code;      
  
    Trie_node *location = root;  //从根结点开始   
    while( location!=NULL && *word!=0 ) {       
        if (*word >= 'A' && *word <= 'Z')   
            char_code = *word-'A';       
        else if (*word>='a' && *word<='z')   
            char_code = *word-'a';       
        else return 0;// 不合法的单词     
        //转入相应分支指针   
        location = location->branch[char_code];       
        position++;       
        word++;    
    }    
    //找到，获取数据，成功返回   
    if ( location != NULL && location->data != NULL ) {       
        strcpy(entry,location->data);       
        return 1;    
    }    
    else  return 0;// 不合法的单词  
}  
int Trie::insert(const char* word, const char* entry) {     
    int result = 1, position = 0;     
    if ( root == NULL ) root = new Trie_node;   //初始插入，根结点为空   
    char char_code;     
    Trie_node *location = root;   //从根结点开始   
    while( location!=NULL && *word!=0 ) {         
        if (*word>='A' && *word<='Z') char_code = *word-'A';         
        else if (*word>='a' && *word<='z') char_code = *word-'a';         
        else return 0;// 不合法的单词      
  
        //不存在此分支   
        if( location->branch[char_code] == NULL )              
            location->branch[char_code] = new Trie_node;    //创建空分支     
  
        //转入分支   
        location = location->branch[char_code];         
        position++;word++;   }     
    if (location->data != NULL) result = 0;//欲插入的单词已经存在      
    else {    //插入数据       
        location->data = new char[strlen(entry)+1];     //分配内存      
        strcpy(location->data, entry);    //给data赋值表明单词存在   
    }     
    return result;    
}  
int main(){     
    Trie t;     
    char entry[100];     
    t.insert("a", "DET");          
    t.insert("abacus","NOUN");     
    t.insert("abalone","NOUN");     
    t.insert("abandon","VERB");     
    t.insert("abandoned","ADJ");    
    t.insert("abashed","ADJ");     
    t.insert("abate","VERB");      
    t.insert("this", "PRON");     
    if (t.trie_search("this", entry))        
        cout<<"'this' was found. pos: "<<entry<<endl;     
    if (t.trie_search("abate", entry))        
        cout<<"'abate' is found. pos: "<<entry<<endl;     
    if (t.trie_search("baby", entry))        
        cout<<"'baby' is found. pos: "<<entry<<endl;     
    else        
        cout<<"'baby' does not exist at all!"<<endl;  
}