Introduction to Practice Problems in C#

Introduction to Practice Problems

Welcome to the practical segment of our C# programming journey! Today, we'll apply the knowledge from past lessons to solve two practice problems using advanced C# data structures: queues, deques, and sorted dictionaries with custom class keys.

First Practice Problem: Implementing Queues with Deques

Analyzing the First Problem Solution

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Second Practice Problem: Using Sorted Dictionaries with Custom Class as a Key

For the second problem, envision a leaderboard for a video game. Players with their scores can be represented as objects of a custom class, then stored in a sorted dictionary for easy and efficient access.

using System;
using System.Collections.Generic;

class Player : IComparable<Player>
{
    public string Name { get; }
    public int Score { get; }

    public Player(string name, int score)
    {
        Name = name;
        Score = score;
    }

    public int CompareTo(Player other)
    {
        int scoreComparison = Score.CompareTo(other.Score);
        if (scoreComparison == 0)
        {
            return Name.CompareTo(other.Name);
        }
        return scoreComparison;
    }

    public override bool Equals(object obj)
    {
        if (this == obj) return true;
        if (obj == null || GetType() != obj.GetType()) return false;
        Player player = (Player)obj;
        return Score == player.Score && Name == player.Name;
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hash = 17;
            hash = hash * 23 + Name.GetHashCode();
            hash = hash * 23 + Score.GetHashCode();
            return hash;
        }
    }

    public override string ToString()
    {
        return $"({Name}, {Score})";
    }

    public static void Main(string[] args)
    {
        SortedDictionary<Player, int> scores = new SortedDictionary<Player, int>();

        Player player1 = new Player("John", 900);
        Player player2 = new Player("Doe", 1000);

        // Adding players to the SortedDictionary
        scores[player1] = player1.Score;
        scores[player2] = player2.Score;

        // Print SortedDictionary
        foreach (var entry in scores)
        {
            Console.WriteLine(entry.Key); // e.g., (John, 900)
        }
    }
}

using System;
using System.Collections.Generic;

class Player : IComparable<Player>
{
    public string Name { get; }
    public int Score { get; }

    public Player(string name, int score)
    {
        Name = name;
        Score = score;
    }

    public int CompareTo(Player other)
    {
        int scoreComparison = Score.CompareTo(other.Score);
        if (scoreComparison == 0)
        {
            return Name.CompareTo(other.Name);
        }
        return scoreComparison;
    }

    public override bool Equals(object obj)
    {
        if (this == obj) return true;
        if (obj == null || GetType() != obj.GetType()) return false;
        Player player = (Player)obj;
        return Score == player.Score && Name == player.Name;
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hash = 17;
            hash = hash * 23 + Name.GetHashCode();
            hash = hash * 23 + Score.GetHashCode();
            return hash;
        }
    }

    public override string ToString()
    {
        return $"({Name}, {Score})";
    }

    public static void Main(string[] args)
    {
        SortedDictionary<Player, int> scores = new SortedDictionary<Player, int>();

        Player player1 = new Player("John", 900);
        Player player2 = new Player("Doe", 1000);

        // Adding players to the SortedDictionary
        scores[player1] = player1.Score;
        scores[player2] = player2.Score;

        // Print SortedDictionary
        foreach (var entry in scores)
        {
            Console.WriteLine(entry.Key); // e.g., (John, 900)
        }
    }
}

This code snippet introduces a Player class for representing players in a video game, implementing the IComparable<Player> interface to allow sorting by score (primary) and name (secondary). Instances of this class are then used as keys in a SortedDictionary<Player, int>, ensuring that players are stored in a manner that is sorted first by their scores and then by their names if scores are equal. This is essential for functionalities like leaderboards, where players need to be ranked efficiently according to their performance.