// See https://aka.ms/new-console-template for more information

using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        List<Mahasiswa> listMhs = new List<Mahasiswa>();

        listMhs.Add(new Mahasiswa(){Nilai = 95, Nama = "Mahasiswa A", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 96, Nama = "Mahasiswa A", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 97, Nama = "Mahasiswa A", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 30, Nama = "Mahasiswa B", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 20, Nama = "Mahasiswa B", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 40, Nama = "Mahasiswa B", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 84, Nama = "Mahasiswa C", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 86, Nama = "Mahasiswa C", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 85, Nama = "Mahasiswa C", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 94, Nama = "Mahasiswa D", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 93, Nama = "Mahasiswa D", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 90, Nama = "Mahasiswa D", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 60, Nama = "Mahasiswa E", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 65, Nama = "Mahasiswa E", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 67, Nama = "Mahasiswa E", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 60, Nama = "Mahasiswa F", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 60, Nama = "Mahasiswa F", Matakuliah = "Matakul 2"});

        listMhs.Add(new Mahasiswa(){Nilai = 70, Nama = "Mahasiswa F", Matakuliah = "Matakul 3"});

        listMhs.Add(new Mahasiswa(){Nilai = 100, Nama = "Mahasiswa G", Matakuliah = "Matakul 1"});

        listMhs.Add(new Mahasiswa(){Nilai = 100, Nama = "Mahasiswa H", Matakuliah = "Matakul 1"});

        // tampilkan 3 mahasiswa dengan nilai rata-rata tertinggi

        // nilai rata-rata dihitung dari total nilai yang mahasiswa tersebut dapatkan dibagi dengan jumlah matakuliah yang mahasiswa tersebut ambil

        Dictionary<string, long> dataMhs = new Dictionary<string, long>();

        foreach (var m in listMhs)

        {

            if (dataMhs.Where(d => d.Key == m.Nama).Count() > 0)

            {

                dataMhs[m.Nama] += m.Nilai;

            }

            else 

            {

                dataMhs.Add(m.Nama, m.Nilai);

            }

        }

​

        // var coba = listMhs.GroupBy(d => d.Nama).Select<string,int>(d => new {

        //     Key = d.

        // });

​

        foreach(KeyValuePair<string, long> n in dataMhs)

        {

            dataMhs[n.Key] = dataMhs[n.Key] / listMhs.Where(d => d.Nama == n.Key).Count();

        }

​

        dataMhs = dataMhs.OrderByDescending(d => d.Value).ToDictionary(d => d.Key, d => d.Value);

​

        int count = 0;

        foreach(KeyValuePair<string, long> n in dataMhs) 

        {

            if (count < 3)

            {

                Console.WriteLine(n.Key + " " + n.Value.ToString());

                count++;

            }

            else 

            {

                break;

            }

        }

​

    }

}

public class Mahasiswa

{

    public int Nilai {get;set;}

    public string Nama {get;set;}

    public string Matakuliah {get;set;}

}