<p>You are given a string <code>s</code> that consists of lowercase English letters.</p>

<p>A string is called <strong>special</strong> if it is made up of only a single character. For example, the string <code>&quot;abc&quot;</code> is not special, whereas the strings <code>&quot;ddd&quot;</code>, <code>&quot;zz&quot;</code>, and <code>&quot;f&quot;</code> are special.</p>

<p>Return <em>the length of the <strong>longest special substring</strong> of </em><code>s</code> <em>which occurs <strong>at least thrice</strong></em>, <em>or </em><code>-1</code><em> if no special substring occurs at least thrice</em>.</p>

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

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

<pre>
<strong>Input:</strong> s = &quot;aaaa&quot;
<strong>Output:</strong> 2
<strong>Explanation:</strong> The longest special substring which occurs thrice is &quot;aa&quot;: substrings &quot;<u><strong>aa</strong></u>aa&quot;, &quot;a<u><strong>aa</strong></u>a&quot;, and &quot;aa<u><strong>aa</strong></u>&quot;.
It can be shown that the maximum length achievable is 2.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abcdef&quot;
<strong>Output:</strong> -1
<strong>Explanation:</strong> There exists no special substring which occurs at least thrice. Hence return -1.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;abcaba&quot;
<strong>Output:</strong> 1
<strong>Explanation:</strong> The longest special substring which occurs thrice is &quot;a&quot;: substrings &quot;<u><strong>a</strong></u>bcaba&quot;, &quot;abc<u><strong>a</strong></u>ba&quot;, and &quot;abcab<u><strong>a</strong></u>&quot;.
It can be shown that the maximum length achievable is 1.
</pre>

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

<ul>
	<li><code>3 &lt;= s.length &lt;= 5 * 10<sup>5</sup></code></li>
	<li><code>s</code> consists of only lowercase English letters.</li>
</ul>


from collections import Counter

def SegmentIntoRepeats(s):
  last = -1
  current = s[0]

  segments = []

  n = len(s)

  for i, ch in enumerate(s[1:]):
    if ch != current:
      segments.append([current, i - last])
      last = i
      current = ch
  
  segments.append([ current, n - last - 1] )
  return segments

def FindLongestTripleOccurrence(text):
  reps = SegmentIntoRepeats(text)

  H = {}

  for letter, count in reps:
    if not letter in H:
      H[letter] = []
    H[letter].append(count)

  for batch in H.keys():
    H[batch] = sorted(H[batch], reverse = True)[:3]
    
  # print(H)

  optimal = -1

  for letter, runs in H.items():
    if sum(runs) < 3:
      continue

    triple = runs[0] - 2
    if len(runs) >= 2:
      if runs[1] == runs[0] - 1:
        triple = max(triple, runs[1])
      else:
        triple = max(triple, runs[1] - 1)
    if len(runs) >= 3:
      triple = max(triple, runs[2])

    optimal = max(optimal, triple)


  if optimal == 0:
    optimal = -1

  return optimal

class Solution:
    def maximumLength(self, s: str) -> int:
        return FindLongestTripleOccurrence(s)

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