High Five

There are two properties in the node student id and scores, to ensure that each student will have at least 5 points, find the average of 5 highest scores for each person.

Have you met this question in a real interview? 

Yes

Example

Given results = [[1,91],[1,92],[2,93],[2,99],[2,98],[2,97],[1,60],[1,58],[2,100],[1,61]]

Return 

java

/**
 * Definition for a Record
 * class Record {
 *     public int id, score;
 *     public Record(int id, int score){
 *         this.id = id;
 *         this.score = score;
 *     }
 * }
 */
public class Solution {
    /**
     * @param results a list of <student_id, score>
     * @return find the average of 5 highest scores for each person
     * Map<Integer, Double> (student_id, average_score)
     */
    public Map<Integer, Double> highFive(Record[] results) {
        // Write your code here
        if (results == null || results.length == 0) {
            return null;
        }
        Map<Integer, PriorityQueue<Integer>> map = new HashMap<>();
        Map<Integer, Double> res = new HashMap<>();
        for (int i = 0; i < results.length; i++) {
            if (map.containsKey(results[i].id)) {
                if (map.get(results[i].id).size() < 5) {
                    map.get(results[i].id).offer(results[i].score);
                } else {
                    map.get(results[i].id).offer(results[i].score);
                    map.get(results[i].id).poll();
                }
            } else {
                PriorityQueue<Integer> heap = new PriorityQueue<>();
                heap.offer(results[i].score);
                map.put(results[i].id, heap);
            }
        }
        for (int val : map.keySet()) {
            int sum = 0;
            while (!map.get(val).isEmpty()) {
                sum += map.get(val).poll();
            }
            res.put(val, sum / 5.0);
        }
        return res;
    }
}