chore: add GlobalUsings.cs with project-wide using directives in data structures

DataStructures/AATree/AATree.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.AATree;
 
 /// <summary>

DataStructures/AVLTree/AVLTree.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.AVLTree;
 
 /// <summary>

DataStructures/AVLTree/AVLTreeNode.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.AVLTree;
 
 /// <summary>

DataStructures/BinarySearchTree/BinarySearchTree.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.BinarySearchTree;
 
 /// <summary>

DataStructures/BitArray.cs

@@ -114,11 +114,7 @@
 // returns true if there inputs aren't equal otherwise false.
 // assumes: the input bit-arrays must have same length.
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 
 namespace DataStructures;
 

DataStructures/Cache/LfuCache.cs

@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-
 namespace DataStructures.Cache;
 
 /// <summary>

DataStructures/Cache/LruCache.cs

@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-
 namespace DataStructures.Cache;
 
 /// <summary>

DataStructures/GlobalUsings.cs

@@ -0,0 +1,16 @@
+// -----------------------------------------------------------------------------
+// Global using directives for the C-Sharp solution.
+// These namespaces are imported globally so they don’t need to be repeatedly declared
+// in individual files, improving readability and reducing boilerplate.
+//
+// Guidelines:
+// - Keep only the most commonly used namespaces here.
+// - Add project-specific namespaces (e.g., Utilities.Extensions) only if they are
+//   required across the majority of files in the project.
+// - Avoid placing rarely used namespaces here to maintain clarity.
+// -----------------------------------------------------------------------------
+
+global using System;                        // Core base classes and fundamental types
+global using System.Collections.Generic;    // Generic collection types (List, Dictionary, etc.)
+global using System.Linq;                   // LINQ query operators for collections
+global using System.Text;                   // Text encoding, StringBuilder, etc.

DataStructures/Graph/DirectedWeightedGraph.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Graph;
 
 /// <summary>

DataStructures/Graph/IDirectedWeightedGraph.cs

@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-
 namespace DataStructures.Graph;
 
 public interface IDirectedWeightedGraph<T>

DataStructures/Hashing/HashTable.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.Hashing.NumberTheory;
 
 namespace DataStructures.Hashing;

DataStructures/Heap/BinaryHeap.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Heap;
 
 /// <summary>

DataStructures/Heap/FibonacciHeap/FHeapNode.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.Heap.FibonacciHeap;
 
 /// <summary>

DataStructures/Heap/FibonacciHeap/FibonacciHeap.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace DataStructures.Heap.FibonacciHeap;
 
 /// <summary>

DataStructures/Heap/MinMaxHeap.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace DataStructures.Heap;
 
 /// <summary>

DataStructures/Heap/PairingHeap/PairingHeap.cs

@@ -1,7 +1,4 @@
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace DataStructures.Heap.PairingHeap;
 
@@ -57,7 +54,7 @@ public T Extract()
     /// </summary>
     public void UpdateKey(T currentValue, T newValue)
     {
-        if(!mapping.ContainsKey(currentValue))
+        if (!mapping.ContainsKey(currentValue))
         {
             throw new ArgumentException("Current value is not present in this heap.");
         }

DataStructures/Heap/PairingHeap/PairingNodeComparer.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Heap.PairingHeap;
 
 /// <summary>

DataStructures/InvertedIndex.cs

@@ -1,6 +1,3 @@
-using System.Collections.Generic;
-using System.Linq;
-
 namespace DataStructures;
 
 /// <summary>

DataStructures/LinkedList/CircularLinkedList/CircularLinkedList.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.LinkedList.CircularLinkedList
 {
     /// <summary>

DataStructures/LinkedList/DoublyLinkedList/DoublyLinkedList.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 using Utilities.Exceptions;
 
 namespace DataStructures.LinkedList.DoublyLinkedList;

DataStructures/LinkedList/SinglyLinkedList/SinglyLinkedList.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.LinkedList.SinglyLinkedList;
 
 public class SinglyLinkedList<T>
@@ -161,7 +158,7 @@ public bool DeleteElement(T element)
     public bool DeleteFirst()
     {
         // checks if the List is empty
-        if(Head is null)
+        if (Head is null)
         {
             return false;
         }
@@ -178,21 +175,21 @@ public bool DeleteFirst()
     public bool DeleteLast()
     {
         // checks if the List is empty
-        if(Head is null)
+        if (Head is null)
         {
             return false;
         }
 
         // checks if the List has only one element
-        if(Head.Next is null)
+        if (Head.Next is null)
         {
             Head = null;
             return true;
         }
 
         // if not, iterates through the list to the second last element and deletes the last one
         SinglyLinkedListNode<T>? secondlast = Head;
-        while(secondlast.Next?.Next is not null)
+        while (secondlast.Next?.Next is not null)
         {
             secondlast = secondlast.Next;
         }

DataStructures/LinkedList/SkipList/SkipList.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 
 namespace DataStructures.LinkedList.SkipList;
 
@@ -49,7 +46,7 @@ public SkipList(int capacity = 255)
         head = new(int.MinValue, default(TValue), maxLevels);
         tail = new(int.MaxValue, default(TValue), maxLevels);
 
-        for(int i = 0; i < maxLevels; i++)
+        for (int i = 0; i < maxLevels; i++)
         {
             head.Next[i] = tail;
         }
@@ -69,7 +66,7 @@ public TValue this[int key]
         get
         {
             var previousNode = GetSkipNodes(key).First();
-            if(previousNode.Next[0].Key == key)
+            if (previousNode.Next[0].Key == key)
             {
                 return previousNode.Next[0].Value!;
             }

DataStructures/Probabilistic/BloomFilter.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Probabilistic;
 
 public class BloomFilter<T> where T : notnull

DataStructures/Probabilistic/CountMinSketch.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.Probabilistic;
 
 public class CountMinSketch<T> where T : notnull

DataStructures/Probabilistic/HyperLogLog.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace DataStructures.Probabilistic;
 
 public class HyperLogLog<T> where T : notnull

DataStructures/Queue/ArrayBasedQueue.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.Queue;
 
 /// <summary>

DataStructures/Queue/ListBasedQueue.cs

@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
 namespace DataStructures.Queue;
 
 /// <summary>

DataStructures/Queue/StackBasedQueue.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Queue;
 
 /// <summary>

DataStructures/RedBlackTree/RedBlackTree.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.RedBlackTree;
 
 /// <summary>

DataStructures/ScapegoatTree/Extensions.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.ScapegoatTree;
 
 public static class Extensions

DataStructures/ScapegoatTree/Node.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.ScapegoatTree;
 
 /// <summary>

DataStructures/ScapegoatTree/ScapegoatTree.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.ScapegoatTree;
 
 /// <summary>

DataStructures/SegmentTrees/SegmentTree.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.SegmentTrees;
 
 /// <summary>

DataStructures/SegmentTrees/SegmentTreeApply.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.SegmentTrees;
 
 /// <summary>

DataStructures/SortedList.cs

@@ -1,5 +1,4 @@
 using System.Collections;
-using System.Collections.Generic;
 
 namespace DataStructures;
 

DataStructures/Stack/ArrayBasedStack.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.Stack;
 
 /// <summary>

DataStructures/Stack/ListBasedStack.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Stack;
 
 /// <summary>

DataStructures/Stack/QueueBasedStack.cs

@@ -1,9 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
 namespace DataStructures.Stack;
 
 public class QueueBasedStack<T>

DataStructures/Timeline.cs

@@ -12,10 +12,7 @@ this data structure can be used to represent an ordered series of dates or times
             330: Constantine move the capital to Constantinople.
 */
 
-using System;
 using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
 
 namespace DataStructures;
 

DataStructures/Tries/Trie.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Tries;
 
 /// <summary>
@@ -70,10 +67,10 @@ public void Remove(string s)
         s += Mark;
         int index = 0;
         TrieNode match = PrefixQuery(s, ref index);
-        while(match.IsLeaf())
+        while (match.IsLeaf())
         {
             char c = match.Value;
-            if(match.Parent == null)
+            if (match.Parent == null)
             {
                 break;
             }

DataStructures/Tries/TrieNode.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace DataStructures.Tries;
 
 /// <summary>

DataStructures/UnrolledList/UnrolledLinkedList.cs

@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-
 namespace DataStructures.UnrolledList;
 
 /// <summary>

DataStructures/UnrolledList/UnrolledLinkedListNode.cs

@@ -1,5 +1,3 @@
-using System;
-
 namespace DataStructures.UnrolledList;
 
 /// <summary>