<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 Trie {
public:
    char val;
    unordered_map<char, Trie*> children;

    priority_queue<string> words3;
    Trie(char val_): val(val_) {}
    Trie(char val_, priority_queue<string> words3_): val(val_), words3(words3_) {}
};
class Solution {
public:
    vector<vector<string>> suggestedProducts(vector<string>& products, string searchWord) {
        // we just sort products in lexi order
        // then products sharing the same prefix with come close
        // or more efficient, we use Trie and store sibling nodes in order
        // typing is searching alone the Trie, return the first 3 in the children

        // build Trie
        Trie* root = new Trie('#');
        for (string product : products) {
            Trie* curr = root;
            for (char c : product) {
                if (curr->children.find(c) == curr->children.end()) {
                    priority_queue<string> pq;
                    pq.push(product);
                    curr->children[c] = new Trie(c, pq);
                } else {
                    priority_queue<string>& pq = curr->children[c]->words3;
                    pq.push(product);
                    if (pq.size() > 3) {
                        pq.pop();
                    }
                }
                curr = curr->children[c];
                cout << c << ": " << curr->words3.size() << ", " << curr->words3.top() << endl;
            }
        }

        vector<vector<string> > result;
        // search
        cout << endl << "Searching!" << endl;
        Trie* curr = root;
        bool endSearching = false;
        for (char c : searchWord) {
            if (endSearching || curr->children.find(c) == curr->children.end()) {
                result.push_back(vector<string>());
                endSearching = true;
            } else {
                vector<string> res3;
                priority_queue<string>& pq = curr->children[c]->words3;
                while (!pq.empty()) {
                    res3.push_back(pq.top());
                    pq.pop();
                }
                reverse(res3.begin(), res3.end());
                result.push_back(res3);
                curr = curr->children[c];
            }
        }
        return result;
    }
};
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