<p>You are given an array of strings <code>products</code> and a string <code>searchWord</code>.</p>

<p>Design a system that suggests at most three product names from <code>products</code> after each character of <code>searchWord</code> is typed. Suggested products should have common prefix with <code>searchWord</code>. If there are more than three products with a common prefix return the three lexicographically minimums products.</p>

<p>Return <em>a list of lists of the suggested products after each character of </em><code>searchWord</code><em> is typed</em>.</p>

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

<pre>
<strong>Input:</strong> products = [&quot;mobile&quot;,&quot;mouse&quot;,&quot;moneypot&quot;,&quot;monitor&quot;,&quot;mousepad&quot;], searchWord = &quot;mouse&quot;
<strong>Output:</strong> [[&quot;mobile&quot;,&quot;moneypot&quot;,&quot;monitor&quot;],[&quot;mobile&quot;,&quot;moneypot&quot;,&quot;monitor&quot;],[&quot;mouse&quot;,&quot;mousepad&quot;],[&quot;mouse&quot;,&quot;mousepad&quot;],[&quot;mouse&quot;,&quot;mousepad&quot;]]
<strong>Explanation:</strong> products sorted lexicographically = [&quot;mobile&quot;,&quot;moneypot&quot;,&quot;monitor&quot;,&quot;mouse&quot;,&quot;mousepad&quot;].
After typing m and mo all products match and we show user [&quot;mobile&quot;,&quot;moneypot&quot;,&quot;monitor&quot;].
After typing mou, mous and mouse the system suggests [&quot;mouse&quot;,&quot;mousepad&quot;].
</pre>

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

<pre>
<strong>Input:</strong> products = [&quot;havana&quot;], searchWord = &quot;havana&quot;
<strong>Output:</strong> [[&quot;havana&quot;],[&quot;havana&quot;],[&quot;havana&quot;],[&quot;havana&quot;],[&quot;havana&quot;],[&quot;havana&quot;]]
<strong>Explanation:</strong> The only word &quot;havana&quot; will be always suggested while typing the search word.
</pre>

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

<ul>
	<li><code>1 &lt;= products.length &lt;= 1000</code></li>
	<li><code>1 &lt;= products[i].length &lt;= 3000</code></li>
	<li><code>1 &lt;= sum(products[i].length) &lt;= 2 * 10<sup>4</sup></code></li>
	<li>All the strings of <code>products</code> are <strong>unique</strong>.</li>
	<li><code>products[i]</code> consists of lowercase English letters.</li>
	<li><code>1 &lt;= searchWord.length &lt;= 1000</code></li>
	<li><code>searchWord</code> consists of lowercase English letters.</li>
</ul>

class Solution {
    vector<Solution*>child;
    Solution * head;
    bool is_end;
public:
    Solution()
    {
        child.resize(26);
        is_end = false;
    }
    void insert(string word)
    {
        if(head==NULL) head = new Solution();
        Solution * temp = head;
        for(char c : word)
        {
            if(temp->child[c-'a']==NULL)
            {
                temp->child[c-'a'] = new Solution();
            }
            temp = temp->child[c-'a'];
        }
        temp->is_end= true;
    }

    void find_word(Solution * s, string  prefix, vector<string>&v)
    {
        if(!s) return;

        if(v.size()>=3) return;

        if(s->is_end)
        {
            v.push_back(prefix);
        }

        bool flag = false;

        for(int i=0; i<26; i++)
        {
            if(s->child[i])
            {
                find_word(s->child[i], prefix + char('a'+i), v);
                flag = true;
            }
        } 

        return;
    }

    vector<string> find_words( string p)
    {
        vector<string>words;
        Solution * temp =head;
        for(char c : p)
        {
            if(temp->child[c-'a']) temp = temp->child[c-'a'];
            else return words;
        }
        find_word( temp,p, words);
        return words;
    }


    vector<vector<string>> suggestedProducts(vector<string>& products, string searchWord) {
        for(int i=0; i<products.size(); i++)
        {
            insert(products[i]);
        }
        vector<vector<string>>answer;

        for(int i=0; i<searchWord.size(); i++)
        {
            string tmp = searchWord.substr(0,i+1);
            vector<string> temp = find_words(tmp);
            answer.push_back(temp);
        }
        return answer;
    }
};

//[["mobile"],["mobile","moneypot","mousepad"],["mousepad"],["mousepad"],["mousepad"]]
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