<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 {
public:

    class TrieNode {
    public:
        TrieNode() {
            for (int i = 0; i < 26; ++i) {
                children[i] = nullptr;
            }
            suggestions = vector<string>();
        }
        array<shared_ptr<TrieNode>, 26> children;
        vector<string> suggestions;
    };

    class Trie {
    public:
        Trie() {
            root = make_shared<TrieNode>();
        }

        void add(string& word) {
            shared_ptr<TrieNode> curr = root;
            for (char ch : word) {
                if (!curr->children[ch-'a'])
                    curr->children[ch-'a'] = make_shared<TrieNode>();
                curr = curr->children[ch-'a'];

                curr->suggestions.push_back(word);
                sort(curr->suggestions.begin(), curr->suggestions.end());
                if (curr->suggestions.size() > 3)
                    curr->suggestions.pop_back();
            }
        }

        vector<string> getSuggestions(string searchWord) {
            shared_ptr<TrieNode> curr = root;
            for (char ch : searchWord) {
                if (!curr->children[ch-'a'])
                    return {};
                curr = curr->children[ch-'a'];
            }
            return curr->suggestions;
        }

    private:
        shared_ptr<TrieNode> root;
    };

    vector<vector<string>> suggestedProducts(vector<string>& products, string searchWord) {
        Trie trie;
        for (string& prod : products)
            trie.add(prod);
        
        vector<vector<string>> ans;
        for (int i = 0; i < searchWord.size(); ++i) {
            ans.push_back(trie.getSuggestions(searchWord.substr(0, i+1)));
        }

        return ans;
    }
};
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