2512. Reward Top K Students

Problem Link

Description

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You are given two string arrays positive_feedback and negative_feedback, containing the words denoting positive and negative feedback, respectively. Note that no word is both positive and negative.

Initially every student has 0 points. Each positive word in a feedback report increases the points of a student by 3, whereas each negative word decreases the points by 1.

You are given n feedback reports, represented by a 0-indexed string array report and a 0-indexed integer array student_id, where student_id[i] represents the ID of the student who has received the feedback report report[i]. The ID of each student is unique.

Given an integer k, return the top k students after ranking them in non-increasing order by their points. In case more than one student has the same points, the one with the lower ID ranks higher.

 

Example 1:

Input: positive_feedback = ["smart","brilliant","studious"], negative_feedback = ["not"], report = ["this student is studious","the student is smart"], student_id = [1,2], k = 2
Output: [1,2]
Explanation: 
Both the students have 1 positive feedback and 3 points but since student 1 has a lower ID he ranks higher.

Example 2:

Input: positive_feedback = ["smart","brilliant","studious"], negative_feedback = ["not"], report = ["this student is not studious","the student is smart"], student_id = [1,2], k = 2
Output: [2,1]
Explanation: 
- The student with ID 1 has 1 positive feedback and 1 negative feedback, so he has 3-1=2 points. 
- The student with ID 2 has 1 positive feedback, so he has 3 points. 
Since student 2 has more points, [2,1] is returned.

 

Constraints:

• 1 <= positive_feedback.length, negative_feedback.length <= 104
• 1 <= positive_feedback[i].length, negative_feedback[j].length <= 100
• Both positive_feedback[i] and negative_feedback[j] consists of lowercase English letters.
• No word is present in both positive_feedback and negative_feedback.
• n == report.length == student_id.length
• 1 <= n <= 104
• report[i] consists of lowercase English letters and spaces ' '.
• There is a single space between consecutive words of report[i].
• 1 <= report[i].length <= 100
• 1 <= student_id[i] <= 109
• All the values of student_id[i] are unique.
• 1 <= k <= n

Solution

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Python3

class Solution:
    def topStudents(self, positive_feedback: List[str], negative_feedback: List[str], report: List[str], student_id: List[int], k: int) -> List[int]:
        heap = []
        pos = set(positive_feedback)
        neg = set(negative_feedback)
        
        def getScore(words):
            score = 0
            
            for x in words.split(" "):
                if x in pos:
                    score += 3
                elif x in neg:
                    score -= 1
            
            return score
        
        for sid, words in zip(student_id, report):
            score = getScore(words)
            
            item = (score, -sid)
            
            if len(heap) == k:
                heappushpop(heap, item)
            else:
                heappush(heap, item)
        
        res = []
        
        while heap:
            score, sid = heappop(heap)
            sid = -sid
            res.append(sid)
        
        return res[::-1]