LeetCode 3527: Find the Most Common Response ·

Table of Contents

LeetCode Bi-Weekly Contest 155 - This article is part of a series.

Part 1: This Article

Part 2: LeetCode 3528: Unit Conversion I

Meta Data
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Difficulty: medium
First Attempt: 2025-04-26

Total time: 10:00.00

Intuition
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Use a Counter to count the occurrences of each response status.
Then, if there are multiple statuses with the same maximum occurrence,
select the lexicographically smallest one by taking the minimum among them.

Approach
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class Solution:
    def findCommonResponse(self, responses: List[List[str]]) -> str:
        from collections import Counter
        l = []
        
        for response in responses:
            l.extend(list(set(response)))
            
        count_map = Counter(l)
        max_occur = max(count_map.values())
        
        status_list = [k for k,v in count_map.items() if v == max_occur]
        return sorted(status_list)[0]

Optimization Based on Runtime Ranking
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We don’t need to create a list l and then update it with all sets of responses before using Counter.
Instead, we can initialize an empty Counter and directly update it with the set(response) during iteration.
Also, to get the lexicographically smallest status, we can simply use min().

class Solution:
    def findCommonResponse(self, responses: List[List[str]]) -> str:
        from collections import Counter
        
        counter = Counter()
        
        for response in responses:
            res = set(response)
            counter.update(res)
    
        max_occur = max(counter.values())
        
        status_list = [k for k,v in counter.items() if v == max_occur]
        return min(status_list)