字典树实现

字典树

#include <iostream>
#include <vector>
using namespace std;
typedef struct TireNode{
    bool isWord;
    TireNode* next[26]{};
    TireNode()
    {
        isWord = false;
        for (auto & i : next) {
            i = nullptr;
        }
    }
}TireNode;

void insert(TireNode* root,string str)
{
    TireNode* ptr = root;
    char ch;
    for(int i=0;i<str.size();i++)
    {
        ch = str.at(i);
        if(ptr->next[ch-'a'] == nullptr)
        {
            ptr->next[ch-'a'] = new TireNode();
        }
        ptr = ptr->next[ch-'a'];
        if(i==str.size()-1)
        {
            ptr->isWord = true;
            break;
        }
    }
}

bool search(TireNode* root,string str)
{
    TireNode* ptr = root;
    char ch;
    for(int i=0;i<str.size();i++)
    {
        ch = str.at(i);
        if(ptr->next[ch-'a']!=nullptr)
        {
            ptr = ptr->next[ch-'a'];
            if(i==(str.size()-1)&&ptr->isWord)
                return true;
        }
    }
    return false;
}

string maxProfix(TireNode* root,string str)
{
    TireNode* ptr = root;
    string s;
    char ch;
    for (int i = 0; i < str.size(); ++i) {
        ch = str.at(i);
        if(ptr->next[ch-'a']!= nullptr)
        {
            s.push_back(ch);
            ptr = ptr->next[ch-'a'];
        }
        else
        {
            break;
        }
    }
    return s;
}

int main() {
    auto * root = new TireNode();
    vector<string> words;
    words.emplace_back("abc");
    words.emplace_back("bcd");
    words.emplace_back("bcde");
    words.emplace_back("bcdef");
    for (const auto& word:words) {
        insert(root,word);
    }
    string s;
    while(cin>>s)
    {
        cout<<"搜索结果："<<search(root,s)<<endl;
        cout<<"最大前缀："<<maxProfix(root,s)<<endl;
    }

}