Ranking

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

namespace Ranking
{
    class Contests
    {
        public string ContestsList { get; set; }
        public string Password { get; set; }
    }

    class Student
    {
        public string Name { get; set; }
        public Dictionary<string, int> Contest { get; set; }
    }
    class Program
    {
        static void Main()
        {
            List<Contests> contest = new List<Contests>();
            List<Student> students = new List<Student>();

            while (true)
            {
                string[] contestsEntry = Console.ReadLine().Split(':');

                if (contestsEntry[0] == "end of contests")
                {
                    break;
                }
                string examName = contestsEntry[0];
                string passwordExam = contestsEntry[1];

                Contests exam = new Contests();
                exam.ContestsList = examName;
                exam.Password = passwordExam;
                contest.Add(exam);
            }

            while (true)
            {
                string[] input = Console.ReadLine().Split("=>");

                if (input[0] == "end of submissions")
                {
                    break;
                }

                string examName = input[0];
                string passwordExam = input[1];
                string username = input[2];
                int points = int.Parse(input[3]);

                Student user = new Student();

                if (contest.Select(x => x.ContestsList).Contains(examName)
                    && contest.Select(x => x.Password).Contains(passwordExam))
                {
                    if (!user.Name.Contains(username))
                    {
                        user.Name = username;
                        user.Contest = new Dictionary<string, int>();
                        user.Contest[examName] = points;
                        students.Add(user);
                    }

                    else if (!user.Contest.ContainsKey(examName))
                    {
                        user.Contest = new Dictionary<string, int>();
                        user.Contest[examName] = points;
                    }

                    else if (user.Contest[examName] < points)
                    {
                        user.Contest[examName] = points;
                    }
                }
            }
            string bestStudent = "";
            int maxPoints = -1;

            foreach (var student in students)
            {
                int pointsCurrentStudent = student.Contest.Sum(x => x.Value);
                if (maxPoints < pointsCurrentStudent)
                {
                    bestStudent = student.Name;
                    maxPoints = pointsCurrentStudent;
                }
            }

            Console.WriteLine($"Best candidate is {bestStudent} with total {maxPoints} points.");
        }
    }
}