3442. Maximum Difference Between Even and Odd Frequency I

Problem Link

Description

---

You are given a string s consisting of lowercase English letters.

Your task is to find the maximum difference diff = freq(a1) - freq(a2) between the frequency of characters a1 and a2 in the string such that:

• a1 has an odd frequency in the string.
• a2 has an even frequency in the string.

Return this maximum difference.

 

Example 1:

Input: s = "aaaaabbc"

Output: 3

Explanation:

• The character 'a' has an odd frequency of 5, and 'b' has an even frequency of 2.
• The maximum difference is 5 - 2 = 3.

Example 2:

Input: s = "abcabcab"

Output: 1

Explanation:

• The character 'a' has an odd frequency of 3, and 'c' has an even frequency of 2.
• The maximum difference is 3 - 2 = 1.

 

Constraints:

• 3 <= s.length <= 100
• s consists only of lowercase English letters.
• s contains at least one character with an odd frequency and one with an even frequency.

Solution

---

Python3

class Solution:
    def maxDifference(self, s: str) -> int:
        counter = Counter(s).values()
        maxOdd, minEven = -inf, inf
 
        for v in counter:
            if v % 2 == 0:
                minEven = min(minEven, v)
            else:
                maxOdd = max(maxOdd, v)
        
        return maxOdd - minEven