<p>Given an array of strings <code>words</code> (<strong>without duplicates</strong>), return <em>all the <strong>concatenated words</strong> in the given list of</em> <code>words</code>.</p>

<p>A <strong>concatenated word</strong> is defined as a string that is comprised entirely of at least two shorter words (not necessarily distinct)&nbsp;in the given array.</p>

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

<pre>
<strong>Input:</strong> words = [&quot;cat&quot;,&quot;cats&quot;,&quot;catsdogcats&quot;,&quot;dog&quot;,&quot;dogcatsdog&quot;,&quot;hippopotamuses&quot;,&quot;rat&quot;,&quot;ratcatdogcat&quot;]
<strong>Output:</strong> [&quot;catsdogcats&quot;,&quot;dogcatsdog&quot;,&quot;ratcatdogcat&quot;]
<strong>Explanation:</strong> &quot;catsdogcats&quot; can be concatenated by &quot;cats&quot;, &quot;dog&quot; and &quot;cats&quot;; 
&quot;dogcatsdog&quot; can be concatenated by &quot;dog&quot;, &quot;cats&quot; and &quot;dog&quot;; 
&quot;ratcatdogcat&quot; can be concatenated by &quot;rat&quot;, &quot;cat&quot;, &quot;dog&quot; and &quot;cat&quot;.</pre>

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

<pre>
<strong>Input:</strong> words = [&quot;cat&quot;,&quot;dog&quot;,&quot;catdog&quot;]
<strong>Output:</strong> [&quot;catdog&quot;]
</pre>

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

<ul>
	<li><code>1 &lt;= words.length &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= words[i].length &lt;= 30</code></li>
	<li><code>words[i]</code> consists of only lowercase English letters.</li>
	<li>All the strings of <code>words</code> are <strong>unique</strong>.</li>
	<li><code>1 &lt;= sum(words[i].length) &lt;= 10<sup>5</sup></code></li>
</ul>

class Trie {
    public:
        Trie() noexcept = default;

        void add(const string& s) {
            Trie* current = this;
            for(const auto c : s) {
                auto& ptr = current->get(c);
                if(!ptr) {
                    ptr = std::make_unique<Trie>();
                }
                current = ptr.get();
            }
            current->end(true);
        }

        constexpr const Trie* get(const char c) const noexcept {
            return m_letters[c-'a'].get();
        }

        constexpr bool end() const noexcept {
            return m_end;
        }

    private:
        constexpr std::unique_ptr<Trie>& get(const char c) noexcept {
            return m_letters[c-'a'];
        }
        constexpr void end(const bool e) noexcept {
            m_end = e;
        }

        bool m_end = false;
        std::array<std::unique_ptr<Trie>, 26> m_letters;
};
class Solution {
public:
    constexpr bool search(const Trie* node, const Trie* root, const string& word, const int index) const noexcept {
        auto t = node->get(word[index]);
        for(auto i = index+1; i < word.size(); ++i) {
            if(t == nullptr) {
                return false;
            }
            else if(t->end() && search(root, root, word, i)) {
                return true;
            }
            t = t->get(word[i]);
        }
        return t != nullptr && t->end();
    }

    vector<string> findAllConcatenatedWordsInADict(vector<string>& words) const {
        std::sort(words.begin(), words.end(), [](const auto& a, const auto& b){
            return (a.size() < b.size()) || (a.size()==b.size() && a < b);
        });

        vector<string> res;
        Trie trie{};
        for(auto&& w : words) {
            if(search(&trie, &trie, w, 0)) {
                res.emplace_back(std::move(w));
            }
            trie.add(w);
        }
        return res;
    }
};
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