Trie implementation -- method II

最新推荐文章于 2024-09-10 21:37:16 发布

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#Trie

本文详细介绍了Trie树（字典树）的数据结构实现及应用。通过C++代码示例展示了如何构建Trie树，包括插入字符串、搜索完整单词及前缀等功能。此外，还提供了一种深度优先遍历的方法来获取所有已存储的字符串。

struct TrieNode {
    bool isEnd;
    vector<TrieNode*> children;
    
    TrieNode():isEnd(false){
        children.resize(26, NULL);
    }
};


class Trie{
    private :
        TrieNode* root;

    public :
    Trie(){
        root = new TrieNode();
    }
    
    void insert(const string& str) {
        TrieNode* runner = root;
        for( int i = 0; i < str.size(); i++){
            int idx = str[i] - 'a';
            if(!runner->children[idx]) {
                runner->children[idx] = new TrieNode();
            }
            runner = runner->children[idx];
        }
        runner->isEnd = true;
    }
    
    bool searchWord(const string& str) {
        TrieNode* runner = root;
        for( int i = 0; i < str.size(); i++ ) {
            int idx = str[i] - 'a';
            if( !runner->children[idx] ) return false;
            runner = runner->children[idx];
        }
        return runner->isEnd;
    }
    
    bool searchPre(const string& pre) {
    }
    
    vector<string> dfs_traverse(){
        string oneRst;
        vector<string> rst;
        helper(root, oneRst, rst);
        return rst;
    }
    
    void helper( TrieNode* runner, string& oneRst, vector<string>& rst ) {
        if(!runner) return;

        if(runner->isEnd) {
            rst.push_back(oneRst);
        }
        
        for( int i = 0; i < 26; i++ ) {
            TrieNode* child = runner->children[i];
            if(child) {
                oneRst.push_back('a' + i);
                helper(child, oneRst, rst);
                oneRst.pop_back();
            }
        }
    }


};