3090. Maximum Length Substring With Two Occurrences

Problem Link

Description

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Given a string s, return the maximum length of a substring such that it contains at most two occurrences of each character.

 

Example 1:

Input: s = "bcbbbcba"

Output: 4

Explanation:

The following substring has a length of 4 and contains at most two occurrences of each character: "bcbbbcba".

Example 2:

Input: s = "aaaa"

Output: 2

Explanation:

The following substring has a length of 2 and contains at most two occurrences of each character: "aaaa".

 

Constraints:

• 2 <= s.length <= 100
• s consists only of lowercase English letters.

Solution

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Python3

class Solution:
    def maximumLengthSubstring(self, s: str) -> int:
        N = len(s)
        res = 0
        i = 0
        counter = Counter()
        
        for j, x in enumerate(s):
            counter[x] += 1
            
            while counter[x] > 2:
                counter[s[i]] -= 1
                i += 1
            
            res = max(res, j - i + 1)
        
        return res