<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>

struct Node {
    Node* links[26];
    int cntEndWith = 0;
    int cntPrefix = 0;
    vector<string> temp; 
    bool containsKey(char ch) {
        return (links[ch - 'a'] != NULL); 
    }
    Node* get(char ch) {
        return links[ch - 'a']; 
    }
    void put(char ch, Node* node) {
        links[ch - 'a'] = node;
    }
    void addWordToTemp(string s) {
        temp.push_back(s);
    }
    void increaseEnd() {
        cntEndWith++; 
    }
    void increasePrefix() {
        cntPrefix++;
    }
    void deleteEnd() {
        cntEndWith--; 
    }
    void reducePrefix() {
        cntPrefix--; 
    }
};
class Trie {
private:
    Node* root; 
public:
    Trie() {
        root = new Node(); 
    }
    void insert(string word) {
        Node* node = root;
        string s = "";
        for (char ch : word) { 
            if (!node->containsKey(ch)) {
                node->put(ch, new Node()); 
            }
            node = node->get(ch);
            node->addWordToTemp(word);
            node->increasePrefix(); 
        }
        node->increaseEnd(); 
    }
    vector<string> countPrefix(string word) {
        Node* node = root;
        for (char ch : word) { 
            if (node->containsKey(ch)) { 
                node = node->get(ch); 
            } else {
                return {}; 
            }
        }
        return node->temp; 
    }
};
class Solution {
public:
    vector<vector<string>> suggestedProducts(vector<string>& products, string target) {
        Trie trie;
        for (const string& product : products) {
            trie.insert(product);
        }
        vector<vector<string>> ans(target.size());
        string s = "";
        for (int i = 0; i < target.size(); i++) {
            s += target[i];
            vector<string> some = trie.countPrefix(s);
            sort(some.begin(), some.end());
            for (int j = 0; j < min(3, (int)some.size()); j++) {
                ans[i].push_back(some[j]);
            }
        }
        return ans;
    }
};

170730