# LeetCode - 2512. Reward Top K Students
### 題目網址：https://leetcode.com/problems/reward-top-k-students/
###### tags: `LeetCode` `Medium` `模擬` `字串`

/*
    -LeetCode format-
    Problem: 2512. Reward Top K Students
    Difficulty: Medium
    
    by Inversionpeter
*/



stringstream ss;

class Solution {
public:
    vector<int> topStudents(vector<string>& positive_feedback, vector<string>& negative_feedback, vector<string>& report, vector<int>& student_id, int k) {
        unordered_set <string> positives(positive_feedback.begin(), positive_feedback.end()), negatives(negative_feedback.begin(), negative_feedback.end());
        unordered_map <int, int> scores;
        vector <vector <int>> students;
        vector <int> answers;
        string nowWord;
        for (int i = 0; i != report.size(); ++i) {
            ss.clear(); ss.str(report[i]);
            while (ss >> nowWord)
                if (positives.count(nowWord))
                    scores[student_id[i]] += 3;
                else if (negatives.count(nowWord)) 
                    --scores[student_id[i]];
        }
        for (auto [id, score] : scores)
            students.push_back({ -score, id });
        sort(students.begin(), students.end());
        for (int i = 0; i < k; ++i)
            answers.push_back(students[i][1]);
        return answers;
    }
};