<p>You are given a string <code>word</code> and an integer <code>k</code>.</p>

<p>A substring <code>s</code> of <code>word</code> is <strong>complete</strong> if:</p>

<ul>
	<li>Each character in <code>s</code> occurs <strong>exactly</strong> <code>k</code> times.</li>
	<li>The difference between two adjacent characters is <strong>at most</strong> <code>2</code>. That is, for any two adjacent characters <code>c1</code> and <code>c2</code> in <code>s</code>, the absolute difference in their positions in the alphabet is <strong>at most</strong> <code>2</code>.</li>
</ul>

<p>Return <em>the number of <strong>complete </strong>substrings of</em> <code>word</code>.</p>

<p>A <strong>substring</strong> is a <strong>non-empty</strong> contiguous sequence of characters in a string.</p>

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

<pre>
<strong>Input:</strong> word = &quot;igigee&quot;, k = 2
<strong>Output:</strong> 3
<strong>Explanation:</strong> The complete substrings where each character appears exactly twice and the difference between adjacent characters is at most 2 are: <u><strong>igig</strong></u>ee, igig<u><strong>ee</strong></u>, <u><strong>igigee</strong></u>.
</pre>

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

<pre>
<strong>Input:</strong> word = &quot;aaabbbccc&quot;, k = 3
<strong>Output:</strong> 6
<strong>Explanation:</strong> The complete substrings where each character appears exactly three times and the difference between adjacent characters is at most 2 are: <strong><u>aaa</u></strong>bbbccc, aaa<u><strong>bbb</strong></u>ccc, aaabbb<u><strong>ccc</strong></u>, <strong><u>aaabbb</u></strong>ccc, aaa<u><strong>bbbccc</strong></u>, <u><strong>aaabbbccc</strong></u>.
</pre>

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

<ul>
	<li><code>1 &lt;= word.length &lt;= 10<sup>5</sup></code></li>
	<li><code>word</code> consists only of lowercase English letters.</li>
	<li><code>1 &lt;= k &lt;= word.length</code></li>
</ul>

class Solution:
    def countCompleteSubstrings(self, word: str, k: int) -> int:
        n = len(word)
        prelen = [0] * n
        start = 0
        i = 0
        while i < n:
            if i == n - 1 or abs(ord(word[i]) - ord(word[i + 1])) > 2:
                for j in range(start, i + 1):
                    prelen[j] = i - j + 1
                start = i + 1
            i += 1

        def aidx(c):
            return ord(c) - ord('a')

        cnt = [[0] * 26]
        for c in word:
            cur_cnt = cnt[-1][:]
            cur_cnt[aidx(c)] += 1
            cnt.append(cur_cnt)

        ans = 0
        for i in range(0, n - k +1):
            for j in range(i + k, n + 1, k):
                if prelen[i] < j - i:
                    continue
                is_complete = 1
                larger_than_k = False
                for ic in range(26):
                    nc = cnt[j][ic] - cnt[i][ic]
                    if nc != 0 and nc != k:
                        is_complete = 0
                    if nc > k:
                        is_complete = 0
                        larger_than_k = True
                        break
                ans += is_complete
                if larger_than_k:
                    break
        return ans



        
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