Question: Question: Candidates can attempt an entrance exam as many times as they wish. The average score of all attempts is considered in the end. Given a list of scores. find the candidate with the highest score [ average score].

```
String scores[][] = {{"Ram","155"}, 
                    {"Shyam","145"},
                    {"Ram","156"},
                    {"Balram","159"},
                    {"Balram","150"},
                    {"Ram","135"},
                    {"Mira","156"},
                    {"Mira","152"},
                    {"Shyam","155"}};

```

Scores are given in two-dimensional array as above. Need suggestions to solve this in efficient way.

Answer: 
To reduce time complexity, you can use specific collections:

```
public static String findMaxScore(String[][] scores) {
    final class Candidate implements Comparable<Candidate> {

        private final String name;
        private int scoreSum;
        private int attempts;

        public Candidate(String name) {
            this.name = name;
        }

        public void score(int score) {
            scoreSum += score;
            attempts++;
        }

        public double avg() {
            return (double)scoreSum / attempts;
        }

        @Override
        public int compareTo(Candidate candidate) {
            return Double.compare(candidate.avg(), avg());
        }
    }

    Map<String, Candidate> map = new HashMap<>();

    for (String[] data : scores) {
        map.putIfAbsent(data[0], new Candidate(data[0]));
        map.get(data[0]).score(Integer.parseInt(data[1]));
    }

    return new TreeSet<>(map.values()).iterator().next().name;
}

```
Also, by this way, You can do the same via `Streams` Api,

```
import java.util.stream.*;
import java.util.*;
public class Solution {
  public static void main (String[] args) {
    String scores[][] = {{"Bob","80"},{"Charles","85"},{"Rob","70"},{"Bob","100"},{"Charles","75"}};

 Map<Object,Double> collectValues = Arrays.stream(scores).collect(Collectors.groupingBy(a->a[0],Collectors.averagingInt(a->Integer.parseInt(a[1]))));

    Map.Entry<Object,Double> MaxMarks = collectValues.entrySet().stream().max((e1,e2)->Double.compare(e1.getValue(), e2.getValue())).get();

    System.out.println(MaxMarks.getKey() + " :: " + MaxMarks.getValue());

}

```