<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 TrieNode {
public:
    char data;
    unordered_map<char, TrieNode*> childrenMap;
    bool isTerminal;

    TrieNode(char ch) {
        this->data = ch;
        isTerminal = false; // Initialize to false
    }
};

void insertInTrie(TrieNode* root, string word) {
    // Base case
    if (word.length() == 0) {
        root->isTerminal = true;
        return;
    }

    char firstChar = word[0];
    TrieNode* childNode;

    if (root->childrenMap.find(firstChar) != root->childrenMap.end()) {
        childNode = root->childrenMap[firstChar];
    } else {
        // Create a new node
        childNode = new TrieNode(firstChar);
        root->childrenMap[firstChar] = childNode;
    }

    insertInTrie(childNode, word.substr(1));
}

bool searchForWord(TrieNode* root, string word, int& index) {
    if (root->isTerminal == true)
        return true;

    char firstChar = word[0];
    TrieNode* childNode;

    if (root->childrenMap.find(firstChar) != root->childrenMap.end()) {
        childNode = root->childrenMap[firstChar];
    } else {
        // Character not present in the trie
        return false;
    }
    index++;
    return searchForWord(childNode, word.substr(1), index);
}
class Solution {
public:
    string replaceWords(vector<string>& dictionary, string sentence) {
        TrieNode* root = new TrieNode('-');
        for (auto x : dictionary)
            insertInTrie(root, x);

        string ans = "";
        int start = 0, end = 0;
        while (end < sentence.length() && start <= end) {
            while (sentence[end] != ' ' && end < sentence.length())
                end++;

            string checkString = sentence.substr(start, end - start);
            int index = 0;
            if (searchForWord(root, checkString, index) == true)
                ans += sentence.substr(start, index);

            else
                ans += checkString;

            if (end < sentence.length())
                ans += " ";
            end++;
            start = end;
        }

        return ans;
    }
};
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