<p>In English, we have a concept called <strong>root</strong>, which can be followed by some other word to form another longer word - let&#39;s call this word <strong>derivative</strong>. For example, when the <strong>root</strong> <code>&quot;help&quot;</code> is followed by the word <code>&quot;ful&quot;</code>, we can form a derivative <code>&quot;helpful&quot;</code>.</p>

<p>Given a <code>dictionary</code> consisting of many <strong>roots</strong> and a <code>sentence</code> consisting of words separated by spaces, replace all the derivatives in the sentence with the <strong>root</strong> forming it. If a derivative can be replaced by more than one <strong>root</strong>, replace it with the <strong>root</strong> that has <strong>the shortest length</strong>.</p>

<p>Return <em>the <code>sentence</code></em> after the replacement.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> dictionary = [&quot;cat&quot;,&quot;bat&quot;,&quot;rat&quot;], sentence = &quot;the cattle was rattled by the battery&quot;
<strong>Output:</strong> &quot;the cat was rat by the bat&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> dictionary = [&quot;a&quot;,&quot;b&quot;,&quot;c&quot;], sentence = &quot;aadsfasf absbs bbab cadsfafs&quot;
<strong>Output:</strong> &quot;a a b c&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= dictionary.length &lt;= 1000</code></li>
	<li><code>1 &lt;= dictionary[i].length &lt;= 100</code></li>
	<li><code>dictionary[i]</code> consists of only lower-case letters.</li>
	<li><code>1 &lt;= sentence.length &lt;= 10<sup>6</sup></code></li>
	<li><code>sentence</code> consists of only lower-case letters and spaces.</li>
	<li>The number of words in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>The length of each word in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>Every two consecutive words in <code>sentence</code> will be separated by exactly one space.</li>
	<li><code>sentence</code> does not have leading or trailing spaces.</li>
</ul>

class Solution {
private:
    class TrieNode{
        public:
            char data;
            TrieNode* children[26];
            bool isTerminal;
            TrieNode(char data){
                this->data = data;
                for(int i = 0;i<26;i++){
                    children[i] = NULL;
                }
                this->isTerminal = false;
            }
    };
    class Trie{
        public:
        TrieNode* root;
        Trie(){
            root = new TrieNode('\0');
        }
        void insertUtil(TrieNode* root,string word){
            if(word.length() == 0){
                root->isTerminal = true;
                return ;
            }
            int index = word[0] - 'a';
            TrieNode* child;
            if(root->children[index] != NULL){
                child = root->children[index];
            }
            else{
                child = new TrieNode(word[0]);
                root->children[index] = child;
            }
            insertUtil(child,word.substr(1));
            // rvjxtlqfnlmwdoezh
        }
        void insert(string word){
            insertUtil(root,word);
        }
        bool isPresent(TrieNode* root,string word,string &output){
            if(root->isTerminal){
                return true;
            }
            if(word[0] == '\0'){
                return false;
            }
            int index = word[0] - 'a';
            if(root->children[index] == NULL){
                return false;
            }
            if(root->children[index] != NULL){
                output += word[0];
                return isPresent(root->children[index],word.substr(1),output);
            }
            return false;
        }
        bool present(string word,string &output){
            return isPresent(root,word,output);
        }
        // void changeIsTerminal(TrieNode* root,string word){
        //     if(word.length() == 0){
        //         root->isTerminal = true;
        //         return ;
        //     }
        //     int index = word[0] - 'a';
        //     if(root == NULL){
        //         return ;
        //     }
        //     // TrieNode* child;
        //     if(root->children[index] != NULL){
        //         changeIsTerminal(root->children[index],word.substr(1));
        //     }
        // }
        // void changeLast(string word){
        //     changeIsTerminal(root,word);
        // }
        // void solve(TrieNode* root, string word, string &output){
        //     if(root->isTerminal == true){
        //         return;
        //     }
        //     int index = word[0] - 'a';
        //     if(root->children[index] != NULL){
        //         output += word[0];
        //         solve(root->children[index],word.substr(1),output);
        //     }
        // }
        // void getString(string word,string &output){
        //     solve(root,word,output);
        // }
    };
public:
    string replaceWords(vector<string>& dictionary, string sentence) {
        Trie* ans = new Trie();
        for(int i = 0;i<dictionary.size();i++){
            ans->insert(dictionary[i]);
        }
        string output = "";
        // int index = 0;
        int i = 0;
        while(i<sentence.length()){
            string temp = "";
            string res = "";
            while(i<sentence.length() && sentence[i] != ' '){
                temp+=sentence[i];
                i++;
            }
            if(ans->present(temp,res)){
                output += res;
                output += ' ';
            }
            else{
                output += temp;
                output += ' ';
            }
            i++;
        }
        output.pop_back();
        return output;
    //     int i = 0;
    //     while(i<sentence.length()){
    //         string temp = "";
    //         while(sentence[i] != ' ' && i<sentence.length()){
    //             temp += sentence[i];
    //             i++;
    //         }
    //         ans->insert(temp);
    //         i++;
    //     }
    //     for(int i = 0;i<dictionary.size();i++){
    //         ans->changeLast(dictionary[i]);
    //     }
    //     string output = "";
    //     int j = 0;
    //     while(j<sentence.length()){
    //         string alter = "";
    //         while(sentence[j] != ' ' && j<sentence.length()){
    //             alter+=sentence[j];
    //             j++;
    //         }
    //         ans->getString(alter,output);
    //         output += ' ';
    //         j++;
    //     }
    //     output.pop_back();
    //     return output;
    // }
    }
};
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