OAiP-Presnyakov_Ilya-Practice_-8/MyList.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Prac8
{
    public class MyList<T> : IEnumerable<T>
    {
        private const int DefaultCapacity = 4;
        private T[] _items;
        private int _count;

        public MyList(int capacity = DefaultCapacity)
        {
            if (capacity < 1)
            {
                capacity = DefaultCapacity;
            }

            _items = new T[capacity];
            _count = 0;
        }

        public int Count => _count;

        public T this[int index]
        {
            get => Get(index);
            set
            {
                ValidateIndex(index);
                _items[index] = value;
            }
        }

        public void Add(T item)
        {
            EnsureCapacity();
            _items[_count] = item;
            _count++;
        }

        public void Insert(int index, T item)
        {
            ValidateInsertIndex(index);
            EnsureCapacity();

            for (int i = _count; i > index; i--)
            {
                _items[i] = _items[i - 1];
            }

            _items[index] = item;
            _count++;
        }

        public void AddRange(MyList<T> otherList)
        {
            if (otherList == null)
            {
                throw new ArgumentNullException(nameof(otherList), "Другой список не должен быть null.");
            }

            MyList<T> source = CreateSafeCopy(otherList);
            EnsureCapacityFor(source.Count);

            foreach (T item in source)
            {
                Add(item);
            }
        }

        public void InsertRange(int index, MyList<T> otherList)
        {
            ValidateInsertIndex(index);

            if (otherList == null)
            {
                throw new ArgumentNullException(nameof(otherList), "Другой список не должен быть null.");
            }

            if (otherList.Count == 0)
            {
                return;
            }

            MyList<T> source = CreateSafeCopy(otherList);
            EnsureCapacityFor(source.Count);

            for (int i = _count - 1; i >= index; i--)
            {
                _items[i + source.Count] = _items[i];
            }

            int insertPosition = index;
            foreach (T item in source)
            {
                _items[insertPosition] = item;
                insertPosition++;
            }

            _count += source.Count;
        }

        public void RemoveAt(int index)
        {
            ValidateIndex(index);

            for (int i = index; i < _count - 1; i++)
            {
                _items[i] = _items[i + 1];
            }

            _count--;
            _items[_count] = default(T);
        }

        public void RemoveLast()
        {
            if (_count == 0)
            {
                throw new InvalidOperationException("Нельзя удалить последний элемент из пустого списка.");
            }

            _count--;
            _items[_count] = default(T);
        }

        public void RemoveRange(int firstIndex, int secondIndex)
        {
            if (_count == 0)
            {
                throw new InvalidOperationException("Список пуст.");
            }

            ValidateIndex(firstIndex);
            ValidateIndex(secondIndex);

            if (firstIndex > secondIndex)
            {
                throw new ArgumentException("Первый индекс не может быть больше второго.");
            }

            int removeCount = secondIndex - firstIndex + 1;

            for (int i = firstIndex; i < _count - removeCount; i++)
            {
                _items[i] = _items[i + removeCount];
            }

            for (int i = _count - removeCount; i < _count; i++)
            {
                _items[i] = default(T);
            }

            _count -= removeCount;
        }

        public void Clear()
        {
            for (int i = 0; i < _count; i++)
            {
                _items[i] = default(T);
            }

            _count = 0;
        }

        public T Get(int index)
        {
            ValidateIndex(index);
            return _items[index];
        }

        public void Print()
        {
            if (_count == 0)
            {
                Console.WriteLine("Список пуст.");
                return;
            }

            for (int i = 0; i < _count; i++)
            {
                Console.WriteLine($"[{i}] {_items[i]}");
            }
        }

        public T Find(Predicate<T> match)
        {
            if (match == null)
            {
                throw new ArgumentNullException(nameof(match), "Предикат не должен быть null.");
            }

            for (int i = 0; i < _count; i++)
            {
                if (match(_items[i]))
                {
                    return _items[i];
                }
            }

            return default(T);
        }

        public void EnsureCapacity()
        {
            if (_count < _items.Length)
            {
                return;
            }

            int newCapacity = _items.Length == 0 ? DefaultCapacity : _items.Length * 2;
            Array.Resize(ref _items, newCapacity);
        }

        public void Sort(int index)
        {
            if (index != 0 && index != 1)
            {
                throw new ArgumentException("Для сортировки используйте 1 - по возрастанию или 0 - по убыванию.");
            }

            if (_count < 2)
            {
                return;
            }

            Comparer<T> comparer = Comparer<T>.Default;
            bool ascending = index == 1;

            for (int i = 0; i < _count - 1; i++)
            {
                int selectedIndex = i;

                for (int j = i + 1; j < _count; j++)
                {
                    int compareResult = comparer.Compare(_items[j], _items[selectedIndex]);

                    if ((ascending && compareResult < 0) || (!ascending && compareResult > 0))
                    {
                        selectedIndex = j;
                    }
                }

                if (selectedIndex != i)
                {
                    T temp = _items[i];
                    _items[i] = _items[selectedIndex];
                    _items[selectedIndex] = temp;
                }
            }
        }

        public void Reverse()
        {
            int left = 0;
            int right = _count - 1;

            while (left < right)
            {
                T temp = _items[left];
                _items[left] = _items[right];
                _items[right] = temp;
                left++;
                right--;
            }
        }

        public void Distinct()
        {
            if (_count < 2)
            {
                return;
            }

            EqualityComparer<T> comparer = EqualityComparer<T>.Default;
            T[] uniqueItems = new T[Math.Max(DefaultCapacity, _count)];
            int uniqueCount = 0;

            for (int i = 0; i < _count; i++)
            {
                bool exists = false;

                for (int j = 0; j < uniqueCount; j++)
                {
                    if (comparer.Equals(_items[i], uniqueItems[j]))
                    {
                        exists = true;
                        break;
                    }
                }

                if (!exists)
                {
                    uniqueItems[uniqueCount] = _items[i];
                    uniqueCount++;
                }
            }

            _items = uniqueItems;
            _count = uniqueCount;
        }

        public IEnumerator<T> GetEnumerator()
        {
            for (int i = 0; i < _count; i++)
            {
                yield return _items[i];
            }
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        private void ValidateIndex(int index)
        {
            if (index < 0 || index >= _count)
            {
                throw new IndexOutOfRangeException("Индекс находится вне границ списка.");
            }
        }

        private void ValidateInsertIndex(int index)
        {
            if (index < 0 || index > _count)
            {
                throw new IndexOutOfRangeException("Индекс для вставки находится вне границ списка.");
            }
        }

        private void EnsureCapacityFor(int additionalItems)
        {
            while (_count + additionalItems > _items.Length)
            {
                int newCapacity = _items.Length == 0 ? DefaultCapacity : _items.Length * 2;
                Array.Resize(ref _items, newCapacity);
            }
        }

        private static MyList<T> CreateSafeCopy(MyList<T> source)
        {
            MyList<T> copy = new MyList<T>(Math.Max(DefaultCapacity, source.Count));
            foreach (T item in source)
            {
                copy.Add(item);
            }

            return copy;
        }
    }
}