<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>

class TrieNode:
    
    def __init__(self):
        self.childrens = [None]*26
        self.isEnd = False
        self.count = 0
        
class Trie:
    
    def __init__(self):
        self.root = TrieNode()
        
    def insert(self,word):
        node = self.root
        for wordChar in word:
            asciiIndex = ord(wordChar) - ord('a')
            if not node.childrens[asciiIndex]:
                node.childrens[asciiIndex] = TrieNode()
            node = node.childrens[asciiIndex]
        node.isEnd = True
        node.count +=1  
    
    def findIndex(self,word,start,curascii):
        for i in range(start,len(word)):
            if ord(word[i]) - ord('a') == curascii:
                return i
        return -1
    
    def dfsHelper(self,node,word,start):
        for i in range(26):
            if node.childrens[i]:
                child = node.childrens[i]
                index = self.findIndex(word,start,i)
                if index != -1:                    
                    if child.isEnd:
                        self.count += child.count
                    self.dfsHelper(child,word,index+1)
    
    def dfs(self,word):
        self.count = 0
        self.dfsHelper(self.root,word,0)
        return self.count         
                
                
class Solution:
    def numMatchingSubseq(self, s: str, words: List[str]) -> int:
        trie = Trie()
        for word in words:
            trie.insert(word)
        return trie.dfs(s)
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