字典树

#include <stdio.h>
#include <string.h>
#include <iostream>
using namespace std;


const int size=26;

struct tire_node
{
	
    bool is_word;
    tire_node(){
		is_word=false;
		for(int i=0;i<26;i++)
			child[i]=NULL;
    }    
    tire_node *child[26];
};

class Tire{
public:
	Tire(){
		root=NULL;
	}
	tire_node *root;
	
	void insert(char *str);
	bool del(char *str);  
	bool search(char *str);        
};
void Tire::insert(char *str){
    if(root==NULL)
		root=new  tire_node();
    
    tire_node *tmp=root;
    
    while(*str!='\0'){
		if(tmp->child[*str-'a']==NULL)
			tmp->child[*str-'a'] = new tire_node;
        
        tmp=tmp->child[*str-'a'];
        str++;
    }
    tmp->is_word=true;
}     
bool Tire::del(char *str){
   	tire_node *tmp=root;

	while(*str!='\0'){
	  if(tmp->child[*str-'a']==NULL)
		  return false;
	   tmp=tmp->child[*str-'a'];
	   str++;
	}

	if(tmp->is_word){
	    tmp->is_word=false;
		return true;
	}
    else
	{
	 return false;
	}
 

}

bool Tire::search(char *str)
{
	tire_node *tmp=root;
	
	while(*str!='\0'){
        if(tmp->child[*str-'a']==NULL)
			return false;
        tmp=tmp->child[*str-'a'];
        str++;
	}   
	return tmp->is_word;              
}

int main()
{
    
    Tire tr;
    
    tr.insert("abc");
    cout<<tr.search("abc")<<endl;
    cout<<tr.search("abcd")<<endl;
	cout<<tr.search("ab")<<endl;

    tr.insert("abcde");
    cout<<tr.del("abcd")<<endl;

	// for(;;); 
    
    
	return 0;    
}