Leetcode #2284: Sender With Largest Word Count
In this guide, we solve Leetcode #2284 Sender With Largest Word Count in Python and focus on the core idea that makes the solution efficient.
You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.
Problem Statement
You have a chat log of n messages. You are given two string arrays messages and senders where messages[i] is a message sent by senders[i].
Quick Facts
- Difficulty: Medium
- Premium: No
- Tags: Array, Hash Table, String, Counting
Intuition
Fast membership checks and value lookups are the heart of this problem, which makes a hash map the natural choice.
By storing what we have already seen (or counts/indexes), we can answer the question in one pass without backtracking.
Approach
Scan the input once, using the map to detect when the condition is satisfied and to update state as you go.
This keeps the solution linear while remaining easy to explain in an interview setting.
Steps:
- Initialize a hash map for seen items or counts.
- Iterate through the input, querying/updating the map.
- Return the first valid result or the final computed value.
Example
Input: messages = ["Hello userTwooo","Hi userThree","Wonderful day Alice","Nice day userThree"], senders = ["Alice","userTwo","userThree","Alice"]
Output: "Alice"
Explanation: Alice sends a total of 2 + 3 = 5 words.
userTwo sends a total of 2 words.
userThree sends a total of 3 words.
Since Alice has the largest word count, we return "Alice".
Python Solution
class Solution:
def largestWordCount(self, messages: List[str], senders: List[str]) -> str:
cnt = Counter()
for message, sender in zip(messages, senders):
cnt[sender] += message.count(" ") + 1
ans = senders[0]
for k, v in cnt.items():
if cnt[ans] < v or (cnt[ans] == v and ans < k):
ans = k
return ans
Complexity
The time complexity is , and the space complexity is , where is the number of messages and is the total length of all messages. The space complexity is , where is the number of messages and is the total length of all messages.
Edge Cases and Pitfalls
Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.
Summary
This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.