<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 Solution:
    def numMatchingSubseq(self, s: str, words: List[str]) -> int:
        def binSearch(arr:List[int], target:int):
            start = 0
            end = len(arr) - 1

            if end == -1:
                return -1

            if arr[start] > target:
                return arr[start]

            if target >= arr[end]:
                return arr[end]

            while start <= end:
                mid = int((start + end)/2)

                if arr[mid] > target:
                    end = mid - 1
                else:
                    start = mid + 1

            return arr[start]

        
        indexArr = [[] for _ in range(26)]
        index = 0

        for c in s:
            indexArr[ord(c) - ord('a')].append(index)
            index += 1

        count = 0
        for word in words:
            
            isSub = True
            lastIndex = -1
            for c in word:
                if binSearch(indexArr[ord(c) - ord('a')],lastIndex) > lastIndex:
                    lastIndex = binSearch(indexArr[ord(c) - ord('a')],lastIndex)
                else:
                    isSub = False
                    break

            if isSub:
                count+=1
        
        return count
                
                
                
                

            



                
        
19500