<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:
        vector<TrieNode*> children;
        bool isEnd;

        TrieNode()
        {
            children.resize(26, NULL);
            isEnd = false;
        }
};

class Solution {
public:

    TrieNode* root;

    Solution() 
    {
        root = new TrieNode();
    }

    vector<string> split(string path)
    {
        size_t first = 0, last = path.find(' ', first);
        vector<string> res;
        while(last != string::npos)
        {
            auto name = path.substr(first, last-first);
            res.push_back(name);
            first = last+1;
            last = path.find(' ', first);
        }
        res.push_back(path.substr(first));
        return res;
    }

    void insert(string word) 
    {
        TrieNode* tmp = root;
        for(auto w:word)
        {
            if(!tmp->children[w-'a'])
            {
                tmp->children[w-'a'] = new TrieNode();
            }
            tmp = tmp->children[w-'a'];
        }
        tmp->isEnd = true;
    }

    string search(string word) 
    {
        TrieNode* tmp = root;
        string g = "";
        for(auto w:word)
        {
            g = g+w;
            if(!tmp->children[w-'a'])
            {
                return word;
            }
            tmp = tmp->children[w-'a'];
            if(tmp->isEnd)
            {
                return g;
            }
        }
        return word;
    }

    string replaceWords(vector<string>& d, string sentence) 
    {
        for(auto w:d)
        {
            insert(w);
        }
        vector<string> s = split(sentence);
        string ans = "";
        int i = 0;
        for(i=0;i<s.size();i++)
        {
            auto w = s[i];
            if(i==s.size()-1)
            {
                ans = ans + search(w);
            }
            else
            {
                ans = ans + search(w) + " ";
            }
        }
        return ans;
    }
};
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