208-Implement-Trie-(Prefix-Tree).cpp

struct Node{
    Node*links[26];
    bool flag=false;
    bool containsKey(char ch)
    {
        return (links[ch-'a'] != NULL);
    }
    void put(char ch,Node*node)
    {
        links[ch-'a'] = node;
    }
    Node*get(char ch)
    {
        return links[ch-'a'];
    }
    bool setEnd()
    {
        flag=true;
        return flag;
    }
    bool isEnd()
    {
        return flag;
    }
};

class Trie {
    Node*root;
public:
    Trie() {
        root = new Node();
    }
    
    void insert(string word) {
        Node*node = root;
        for(int i=0;i<word.length();i++)
        {
            if(!node->containsKey(word[i]))
            {
                node->put(word[i],new Node());
            }
            node=node->get(word[i]);
        }
        node->setEnd();
    }
    
    bool search(string word) {
        Node*node=root;

        for(int i=0;i<word.length();i++)
        {
            if(!node->containsKey(word[i]))
            {
                return false;
            }
            node = node->get(word[i]);
        }
        return node->isEnd();
    }
    
    bool startsWith(string word) {
        Node*node = root;

        for(int i=0;i<word.length();i++)
        {
            if(!node->containsKey(word[i]))
            {
                return false;
            }
            node = node->get(word[i]);
        }
        return true;
    }
};

/**
 * Your Trie object will be instantiated and called as such:
 * Trie* obj = new Trie();
 * obj->insert(word);
 * bool param_2 = obj->search(word);
 * bool param_3 = obj->startsWith(prefix);
 */