Implement Singly Linked List

Author: hamednikzad

TODO.md

@@ -8,7 +8,7 @@ Here is Data Structures base on https://en.wikipedia.org/wiki/List_of_data_struc
 
 ### Abstract data types
 - [x] ArrayList
-- [ ] List
+- [x] List
 - [ ] Tuple
 - [ ] Associative array, Map
 - [ ] Multimap
@@ -41,7 +41,7 @@ Here is Data Structures base on https://en.wikipedia.org/wiki/List_of_data_struc
  - [ ] Iliffe vector
  - [ ] Variable-length array
  - [ ] List
- - [ ] Simple Linked List
+ - [x] Singly Linked List
  - [ ] Doubly Linked List
  - [ ] Circular Linked List
  - [ ] Doubly Circular Linked List

src/ConsoleApp/Program.cs

@@ -1,8 +1,10 @@
 using DataStructures.AbstractDataTypes.Arrays;
+using DataStructures.AbstractDataTypes.Lists;
 
 //ArrayUsage();
 //ArrayListUsage();
-ListUsage();
+//ListUsage();
+LinkedListUsage();
 
 
 void ArrayUsage()
@@ -28,8 +30,24 @@ void ListUsage()
  3,
  4
  };
+ 
  foreach (var item in list)
  {
  Console.WriteLine(item);
  }
-}
+}
+
+void LinkedListUsage()
+{
+ var ll = new NikSinglyLinkedList<int>();
+ ll.AddLast(5);
+ ll.AddLast(2);
+ ll.AddLast(3);
+
+ foreach (var i in ll)
+ {
+ Console.WriteLine(i);
+ }
+
+ ll.Remove(3);
+} 

src/DataStructures/AbstractDataTypes/Arrays/NikArrayList.cs renamed to src/DataStructures/AbstractDataTypes/Lists/NikArrayList.cs

@@ -1,7 +1,7 @@
 using System.Collections;
 // ReSharper disable All
 
-namespace DataStructures.AbstractDataTypes.Arrays;
+namespace DataStructures.AbstractDataTypes.Lists;
 
 public class NikArrayList
 {

src/DataStructures/AbstractDataTypes/Arrays/NikList.cs renamed to src/DataStructures/AbstractDataTypes/Lists/NikList.cs

@@ -2,7 +2,7 @@
 
 // ReSharper disable ConvertToAutoPropertyWithPrivateSetter
 
-namespace DataStructures.AbstractDataTypes.Arrays;
+namespace DataStructures.AbstractDataTypes.Lists;
 
 public class NikList<T> : IEnumerable<T>
 {

src/DataStructures/AbstractDataTypes/Lists/NikSinglyLinkedList.cs

@@ -0,0 +1,130 @@
+using System.Collections;
+
+namespace DataStructures.AbstractDataTypes.Lists;
+
+public class NikSinglyLinkedList<T> : IEnumerable<T>
+{
+ public class Node
+ {
+ public Node(T value)
+ {
+ Value = value;
+ }
+
+ public Node? Next { get; set; }
+ public T Value { get; }
+ }
+
+ private Node? _head;
+ private int _count;
+
+ public int Count => _count;
+
+ public void AddFirst(T value)
+ {
+ var newNode = new Node(value);
+
+ if (_head is null)
+ {
+ _head = newNode;
+ _count++;
+ return;
+ }
+
+ newNode.Next = _head;
+ _head = newNode;
+ }
+
+ public void AddLast(T value)
+ {
+ var newNode = new Node(value);
+
+ if (_head is null)
+ {
+ _head = newNode;
+ _count++;
+ return;
+ }
+
+ var current = _head;
+ while (current.Next is not null)
+ {
+ current = current.Next;
+ }
+
+ current.Next = newNode;
+ _count++;
+ }
+
+ public bool Contains(T value)
+ {
+ return Find(value) != null;
+ }
+
+ public bool Remove(T value)
+ {
+ if (_head is null)
+ return false;
+ 
+ var comparer = EqualityComparer<T>.Default;
+ if (comparer.Equals(_head.Value, value))
+ {
+ _head = _head.Next;
+ _count--;
+ return true;
+ }
+ 
+ var current = _head;
+ var prev = _head;
+ while (current is not null)
+ {
+ if (comparer.Equals(current.Value, value))
+ {
+ prev.Next = current.Next;
+ _count--;
+ return true;
+ }
+
+ prev = current;
+ current = current.Next;
+ }
+
+ return false;
+ }
+ 
+ private Node? Find(T value)
+ {
+ if (_head is null)
+ return null;
+
+ var current = _head;
+ var comparer = EqualityComparer<T>.Default;
+ while (current is not null)
+ {
+ if (comparer.Equals(current.Value, value))
+ return current;
+
+ current = current.Next;
+ }
+
+ return null;
+ }
+ 
+ public IEnumerator<T> GetEnumerator()
+ {
+ if (_head is null)
+ yield break;
+
+ var current = _head;
+ while (current is not null)
+ {
+ yield return current.Value;
+ current = current.Next;
+ }
+ }
+
+ IEnumerator IEnumerable.GetEnumerator()
+ {
+ return GetEnumerator();
+ }
+}