<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 value;
    TrieNode *children[26];
    bool isTerminal;
    TrieNode(char val)
    {
        this->value = val;
        for (int i = 0; i < 26; i++)
            children[i] = NULL;
        this->isTerminal = false;
    }
};

class Solution {
public:
    void insertWord(TrieNode *root, string word)
    {
        if (word.size() == 0)
        {
            root->isTerminal = true;
            return;
        }
        TrieNode *child;
        char ch = word[0];
        int index = ch - 'a';
        if (root->children[index] != NULL)
            child = root->children[index];
        else
        {
            child = new TrieNode(ch);
            root->children[index] = child;
        }
        insertWord(child, word.substr(1));
    }
    string getRoot(string ogWord, string s, TrieNode *root, string &rWord)
    {
        char ch = s[0];
        int index = ch - 'a';
        if (s.size() == 0)
            return ogWord;
        if (root->isTerminal == true)
        {
            return rWord;
        }
        if (root->children[index] == NULL)
            return ogWord;
        rWord += ch;
        return getRoot(ogWord, s.substr(1), root->children[index], rWord);
    }
    string replaceWords(vector<string>& dictionary, string sentence)
    {
        TrieNode *root = new TrieNode('-');
    for (auto word : dictionary)
    {
        insertWord(root, word);
    }
    string s = "";
    sentence += ' ';
    string ans = "";
    for (auto ch : sentence)
    {
        if (ch != ' ')
            s += ch;
        else
        {
            string rWord = "";
            ans += getRoot(s, s, root, rWord) + ' ';
            s = "";
        }
    }
    ans.pop_back();
    // cout<<ans<<endl;
    return ans;
    }
};
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