3527. Find the Most Common Response

Problem Link

Description

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You are given a 2D string array responses where each responses[i] is an array of strings representing survey responses from the ith day.

Return the most common response across all days after removing duplicate responses within each responses[i]. If there is a tie, return the lexicographically smallest response.

 

Example 1:

Input: responses = [["good","ok","good","ok"],["ok","bad","good","ok","ok"],["good"],["bad"]]

Output: "good"

Explanation:

• After removing duplicates within each list, responses = [["good", "ok"], ["ok", "bad", "good"], ["good"], ["bad"]].
• "good" appears 3 times, "ok" appears 2 times, and "bad" appears 2 times.
• Return "good" because it has the highest frequency.

Example 2:

Input: responses = [["good","ok","good"],["ok","bad"],["bad","notsure"],["great","good"]]

Output: "bad"

Explanation:

• After removing duplicates within each list we have responses = [["good", "ok"], ["ok", "bad"], ["bad", "notsure"], ["great", "good"]].
• "bad", "good", and "ok" each occur 2 times.
• The output is "bad" because it is the lexicographically smallest amongst the words with the highest frequency.

 

Constraints:

• 1 <= responses.length <= 1000
• 1 <= responses[i].length <= 1000
• 1 <= responses[i][j].length <= 10
• responses[i][j] consists of only lowercase English letters

Solution

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Python3

class Solution:
    def findCommonResponse(self, responses: List[List[str]]) -> str:
        counter = Counter()
 
        for resp in responses:
            s = set()
 
            for x in resp:
                if x in s: continue
                counter[x] += 1
                s.add(x)
 
        ans, count = None, 0
 
        for k, v in counter.items():
            if ans is None or v > count or (v == count and k < ans):
                ans, count = k, v
 
        return ans