P02lab

using System;
using System.Linq;
using System.Collections.Generic;

namespace LabP01CountSameValuesInArray
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, List<decimal>> map = new Dictionary<string, List<decimal>>();

            int n = int.Parse(Console.ReadLine());

            for (int i = 0; i < n; i++)
            {
                string[] input = Console.ReadLine()
                    .Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries)
                    .ToArray();

                string name = input[0];
                decimal grade = decimal.Parse(input[1]);

                if (map.ContainsKey(name) == false)
                {
                    map.Add(name, new List<decimal>());
                }

                map[name].Add(grade);
            }

            foreach (var student in map)
            {
                var nameOfStudent = student.Key;
                var listOfGrades = student.Value;
                decimal average = listOfGrades.Average();

                Console.WriteLine($"{nameOfStudent} -> {string.Join(" ",listOfGrades):F2} (avg: {average:f2})");
            }
        }
    }
}