<p>Given a string <code>s</code> and an array of strings <code>words</code>, return <em>the number of</em> <code>words[i]</code> <em>that is a subsequence of</em> <code>s</code>.</p>

<p>A <strong>subsequence</strong> of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.</p>

<ul>
	<li>For example, <code>&quot;ace&quot;</code> is a subsequence of <code>&quot;abcde&quot;</code>.</li>
</ul>

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

<pre>
<strong>Input:</strong> s = &quot;abcde&quot;, words = [&quot;a&quot;,&quot;bb&quot;,&quot;acd&quot;,&quot;ace&quot;]
<strong>Output:</strong> 3
<strong>Explanation:</strong> There are three strings in words that are a subsequence of s: &quot;a&quot;, &quot;acd&quot;, &quot;ace&quot;.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;dsahjpjauf&quot;, words = [&quot;ahjpjau&quot;,&quot;ja&quot;,&quot;ahbwzgqnuk&quot;,&quot;tnmlanowax&quot;]
<strong>Output:</strong> 2
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 5 * 10<sup>4</sup></code></li>
	<li><code>1 &lt;= words.length &lt;= 5000</code></li>
	<li><code>1 &lt;= words[i].length &lt;= 50</code></li>
	<li><code>s</code> and <code>words[i]</code> consist of only lowercase English letters.</li>
</ul>

struct TrieNode {
    unordered_map<char, TrieNode*> next;
    int wordCount;
    TrieNode() : wordCount(0) {}
};

class Solution {
public:
    int numMatchingSubseq(string s, vector<string>& words) {
        int count = 0;
        TrieNode *root = new TrieNode();
        
        // Build the Trie
        for (string word : words) {
            TrieNode *curr = root;
            for (char ch : word) {
                if (!curr->next.count(ch)) {
                    curr->next[ch] = new TrieNode();
                }
                curr = curr->next[ch];
            }
            curr->wordCount++;
        }

        // Vector of queues to store pointers to Trie nodes waiting for each character
        unordered_map<char, queue<TrieNode*>> pointers;
        
        // Initialize the pointers with the first level of children nodes
        for (auto& entry : root->next) {
            pointers[entry.first].push(entry.second);
        }

        // Traverse the string `s` and move through the Trie accordingly
        for (char ch : s) {
            int sz = pointers[ch].size();
            while (sz--) {
                TrieNode *p = pointers[ch].front();
                pointers[ch].pop();
                count += p->wordCount;
                
                // Add the next level of children to the corresponding queues
                for (auto& entry : p->next) {
                    pointers[entry.first].push(entry.second);
                }
            }
        }
        
        return count;
    }
};


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