diff --git a/Arrays/Anagram_Check_manual_Sol.py b/Arrays/AnagramCheckManualSol.py
similarity index 100%
rename from Arrays/Anagram_Check_manual_Sol.py
rename to Arrays/AnagramCheckManualSol.py
diff --git a/Arrays/Anagram_Check_Sorted_Sol.py b/Arrays/AnagramCheckSortedSol.py
similarity index 100%
rename from Arrays/Anagram_Check_Sorted_Sol.py
rename to Arrays/AnagramCheckSortedSol.py
diff --git a/Arrays/ArrayFindTheMissingElement_brute_force_sol.py b/Arrays/ArrayFindTheMissingElementBruteForceSol.py
similarity index 100%
rename from Arrays/ArrayFindTheMissingElement_brute_force_sol.py
rename to Arrays/ArrayFindTheMissingElementBruteForceSol.py
diff --git a/Arrays/ArrayFindTheMissingElement_hash_table_sol.py b/Arrays/ArrayFindTheMissingElementHashTableSol.py
similarity index 100%
rename from Arrays/ArrayFindTheMissingElement_hash_table_sol.py
rename to Arrays/ArrayFindTheMissingElementHashTableSol.py
diff --git a/Arrays/ArrayFindTheMissingElement_takingSumandSubtract_sol.py b/Arrays/ArrayFindTheMissingElementSumSol.py
similarity index 100%
rename from Arrays/ArrayFindTheMissingElement_takingSumandSubtract_sol.py
rename to Arrays/ArrayFindTheMissingElementSumSol.py
diff --git a/Arrays/ArrayFindTheMissingElement_XOR_sol.py b/Arrays/ArrayFindTheMissingElementXORSol.py
similarity index 100%
rename from Arrays/ArrayFindTheMissingElement_XOR_sol.py
rename to Arrays/ArrayFindTheMissingElementXORSol.py
diff --git a/Arrays/README.md b/Arrays/README.md
index 707a82e..6a3de28 100644
--- a/Arrays/README.md
+++ b/Arrays/README.md
@@ -4,10 +4,10 @@ This directory contains Python implementations of common array-based algorithms
 
 ## Contents
 
-- [Anagram Check (Sorted Solution)](Anagram_Check_Sorted_Sol.py): Checks if two strings are anagrams by comparing their sorted versions.
-- [Anagram Check (Manual Solution)](Anagram_Check_manual_Sol.py): Checks if two strings are anagrams using a hash table (dictionary) to count character frequencies.
-- [Array Find Missing Element (XOR Solution)](ArrayFindTheMissingElement_XOR_sol.py): Efficiently finds a missing element in a shuffled array using bitwise XOR.
-- [Array Find Missing Element (Brute Force Solution)](ArrayFindTheMissingElement_brute_force_sol.py): Finds a missing element by sorting both arrays and comparing them.
-- [Array Find Missing Element (Hash Table Solution)](ArrayFindTheMissingElement_hash_table_sol.py): Finds a missing element using a hash table (dictionary) to track element counts.
-- [Array Find Missing Element (Sum/Subtract Solution)](ArrayFindTheMissingElement_takingSumandSubtract_sol.py): Finds a missing element by calculating the difference between the sums of the two arrays.
+- [Anagram Check (Sorted Solution)](AnagramCheckSortedSol.py): Checks if two strings are anagrams by comparing their sorted versions.
+- [Anagram Check (Manual Solution)](AnagramCheckManualSol.py): Checks if two strings are anagrams using a hash table (dictionary) to count character frequencies.
+- [Array Find Missing Element (XOR Solution)](ArrayFindTheMissingElementXORSol.py): Efficiently finds a missing element in a shuffled array using bitwise XOR.
+- [Array Find Missing Element (Brute Force Solution)](ArrayFindTheMissingElementBruteForceSol.py): Finds a missing element by sorting both arrays and comparing them.
+- [Array Find Missing Element (Hash Table Solution)](ArrayFindTheMissingElementHashTableSol.py): Finds a missing element using a hash table (dictionary) to track element counts.
+- [Array Find Missing Element (Sum/Subtract Solution)](ArrayFindTheMissingElementSumSol.py): Finds a missing element by calculating the difference between the sums of the two arrays.
 - [Array Pair Sum Solution](ArrayPairSumSol.py): Finds all unique pairs in an array that sum up to a specific value $k$ using a set for $O(n)$ complexity.
diff --git a/deque/DequeImple.py b/Deque/DequeImple.py
similarity index 100%
rename from deque/DequeImple.py
rename to Deque/DequeImple.py
diff --git a/deque/README.md b/Deque/README.md
similarity index 72%
rename from deque/README.md
rename to Deque/README.md
index 046a17f..3b002e0 100644
--- a/deque/README.md
+++ b/Deque/README.md
@@ -4,4 +4,4 @@ This directory contains Python implementations of the Deque (Double-Ended Queue)
 
 ## Contents
 
-- [Deque Implementation](DequeImple.py): Basic implementation of a Deque using a Python list. Includes operations like `addFront`, `addRear`, `removeFront`, `removeRear`, `isEmpty`, and `size`.
+- [Deque Implementation](DequeImple.py): Basic implementation of a Deque using a Python list. Includes operations like `addFront` and `removeFront` ($O(1)$), and `addRear` and `removeRear` ($O(n)$), `isEmpty`, and `size`.
diff --git a/Error-debug/ErrorExceptions.py b/ErrorHandling/ErrorExceptions.py
similarity index 100%
rename from Error-debug/ErrorExceptions.py
rename to ErrorHandling/ErrorExceptions.py
diff --git a/Error-debug/README.md b/ErrorHandling/README.md
similarity index 100%
rename from Error-debug/README.md
rename to ErrorHandling/README.md
diff --git a/LinkedLists/README.md b/LinkedLists/README.md
index bead21d..91263c9 100644
--- a/LinkedLists/README.md
+++ b/LinkedLists/README.md
@@ -4,8 +4,8 @@ This directory contains Python implementations of various types of linked lists
 
 ## Contents
 
-- [Singly Linked List Implementation](SingleLinkedListImple.py): Basic implementation of a singly linked list node and basic linkage.
+- [Singly Linked List Implementation](SinglyLinkedListImple.py): Basic implementation of a singly linked list node and basic linkage.
 - [Doubly Linked List Implementation](DoublyLinkedListImple.py): Basic implementation of a doubly linked list node with `prev` and `next` pointers.
-- [Singly Linked List Cycle Check](SinglyLinkedListCycleCheckImple.py): Implements Floyd's Cycle-Finding Algorithm (two pointers) to detect cycles in a linked list.
+- [Singly Linked List Cycle Check](SinglyLinkedListCycleCheckImple.py): Implements Floyd's Cycle-Finding Algorithm (two pointers) to detect cycles in a linked list. $O(n)$ time complexity.
 - [Linked List Reversal](LinkedListReversal.py): Reverses a singly linked list in-place in $O(n)$ time.
-- [Nth to Last Node](LinkedListNthToLastNode.py): Finds the $n$-th to last node in a singly linked list using two pointers.
+- [Nth to Last Node](LinkedListNthToLastNode.py): Finds the $n$-th to last node in a singly linked list using two pointers. $O(n)$ complexity.
diff --git a/LinkedLists/SinglyLinkedListCycleCheckImple.py b/LinkedLists/SinglyLinkedListCycleCheckImple.py
index 71a1b5c..90603e5 100644
--- a/LinkedLists/SinglyLinkedListCycleCheckImple.py
+++ b/LinkedLists/SinglyLinkedListCycleCheckImple.py
@@ -19,10 +19,10 @@ def __init__(self, value):
         self.value = value
         self.nextnode = None
         
-    def cycle_check(node):
+    def cycle_check(self):
         # Set two pointers initialize to passed node
-        pt1 = node
-        pt2 = node
+        pt1 = self
+        pt2 = self
         # loop through end of the list
         while pt2 != None and pt2.nextnode != None:
             pt1 = pt1.nextnode
@@ -53,5 +53,3 @@ def cycle_check(node):
 # If called as LinkedListNode.cycle_check(a) it should work if it was just a function.
 
 print(a.cycle_check())
-
-
diff --git a/LinkedLists/SingleLinkedListImple.py b/LinkedLists/SinglyLinkedListImple.py
similarity index 100%
rename from LinkedLists/SingleLinkedListImple.py
rename to LinkedLists/SinglyLinkedListImple.py
diff --git a/README.md b/README.md
index b8de7d5..70e07ad 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,7 @@ Most scripts in this repository are standalone and can be executed directly:
 
 ```bash
 # Run any Python script
-python3 Arrays/Anagram_Check_Sorted_Sol.py
+python3 Arrays/AnagramCheckSortedSol.py
 
 # Or run from the repo root
 python3 Sorting/BubbleSortImple.py
@@ -80,7 +80,8 @@ python3 Sorting/BubbleSortImple.py
 ```
 .
 ├── Arrays/              # 🔤 Array-based problems and algorithms
-├── Error-debug/         # ⚠️ Error handling and debugging examples
+├── Deque/               # 🔄 Double-ended queue
+├── ErrorHandling/       # ⚠️ Error handling and debugging examples
 ├── GraphAlgorithms/     # 🗺️ Graph traversal (BFS, DFS) and pathfinding
 ├── LinkedLists/         # 🔗 Singly and Doubly Linked Lists
 ├── Queues/              # 📦 Queue implementations (FIFO)
@@ -88,7 +89,6 @@ python3 Sorting/BubbleSortImple.py
 ├── Sorting/             # 📊 Common sorting algorithms
 ├── Stacks/              # 📚 Stack implementations and applications
 ├── Trees/               # 🌳 Binary Trees, BSTs, Heaps, and Traversals
-├── deque/               # 🔄 Double-ended queue
 ├── CONTRIBUTING.md      # 🤝 Contribution guidelines
 ├── LICENSE              # 📄 MIT License
 └── README.md            # 📖 This file
@@ -100,21 +100,21 @@ python3 Sorting/BubbleSortImple.py
 
 ### Arrays 🔤
 Common array-based algorithms and manipulations.
-- [Anagram Check](Arrays/): [Sorted](Arrays/Anagram_Check_Sorted_Sol.py) & [Manual](Arrays/Anagram_Check_manual_Sol.py) solutions
+- [Anagram Check](Arrays/): [Sorted](Arrays/AnagramCheckSortedSol.py) & [Manual](Arrays/AnagramCheckManualSol.py) solutions
 - [Array Pair Sum](Arrays/ArrayPairSumSol.py): Find pairs that sum to $k$
-- [Find Missing Element](Arrays/): [XOR](Arrays/ArrayFindTheMissingElement_XOR_sol.py), [Brute Force](Arrays/ArrayFindTheMissingElement_brute_force_sol.py), [Hash Table](Arrays/ArrayFindTheMissingElement_hash_table_sol.py), & [Sum](Arrays/ArrayFindTheMissingElement_takingSumandSubtract_sol.py) approaches
+- [Find Missing Element](Arrays/): [XOR](Arrays/ArrayFindTheMissingElementXORSol.py), [Brute Force](Arrays/ArrayFindTheMissingElementBruteForceSol.py), [Hash Table](Arrays/ArrayFindTheMissingElementHashTableSol.py), & [Sum](Arrays/ArrayFindTheMissingElementSumSol.py) approaches
 
 ### Linked Lists 🔗
 Implementations and problems involving linked structures.
-- [Singly Linked List](LinkedLists/SingleLinkedListImple.py) & [Doubly Linked List](LinkedLists/DoublyLinkedListImple.py)
-- [Cycle Detection](LinkedLists/SinglyLinkedListCycleCheckImple.py): Detect cycles using two pointers (Floyd's algorithm)
-- [Reverse Linked List](LinkedLists/LinkedListReversal.py): In-place reversal
-- [Nth to Last Node](LinkedLists/LinkedListNthToLastNode.py): Find the $n$-th node from the end
+- [Singly Linked List](LinkedLists/SinglyLinkedListImple.py) & [Doubly Linked List](LinkedLists/DoublyLinkedListImple.py)
+- [Cycle Detection](LinkedLists/SinglyLinkedListCycleCheckImple.py): Detect cycles using two pointers (Floyd's algorithm) - $O(n)$
+- [Reverse Linked List](LinkedLists/LinkedListReversal.py): In-place reversal - $O(n)$
+- [Nth to Last Node](LinkedLists/LinkedListNthToLastNode.py): Find the $n$-th node from the end - $O(n)$
 
 ### Stacks 📚
 LIFO (Last-In-First-Out) data structures.
-- [Stack Implementation](Stacks/StackImple.py): Basic operations (push, pop, peek)
-- [Balanced Parentheses](Stacks/BalanceParenthlessCheckImple.py): Check for balanced brackets using a stack
+- [Stack Implementation](Stacks/StackImple.py): Basic operations (push, pop, peek) - $O(1)$
+- [Balanced Parentheses](Stacks/BalanceParenthesesCheckImple.py): Check for balanced brackets using a stack - $O(n)$
 
 ### Queues 📦
 FIFO (First-In-First-Out) data structures.
@@ -123,17 +123,17 @@ FIFO (First-In-First-Out) data structures.
 
 ### Deque 🔄
 Double-ended queue operations.
-- [Deque Implementation](deque/DequeImple.py): Operations at both ends
+- [Deque Implementation](Deque/DequeImple.py): Operations at both ends. `addFront`/`removeFront` are $O(1)$, `addRear`/`removeRear` are $O(n)$.
 
 ### Trees 🌳
 Hierarchical data structures.
-- [Binary Search Tree](Trees/BinarySearchTreesImple.py): Complete BST implementation
+- [Binary Search Tree](Trees/BinarySearchTreesImple.py): Complete BST implementation. Average $O(\log n)$, Worst $O(n)$.
 - [BST Validation](Trees/): [Solution 1 (In-order)](Trees/BinarySearchTreeCheckImpleSol1.py) & [Solution 2 (Range check)](Trees/BinarySearchTreeCheckImpleSol2.py)
-- [Binary Search](Trees/): [Iterative](Trees/BinarySearchImple.py) & [Recursive](Trees/BinarySearchRecursiveImple.py)
+- [Binary Search](Trees/): [Iterative](Trees/BinarySearchImple.py) & [Recursive](Trees/BinarySearchRecursiveImple.py) - $O(\log n)$
 - [Binary Heap](Trees/BinaryHeapImple.py): Min-heap implementation
 - [Tree Traversals](Trees/TreeLevelOrderPrintImple.py): Level order (BFS) printing
 - [Trim BST](Trees/TrimBinarySearchTreeImple.py): Keep nodes within a range
-- [Tree Representations](Trees/): [Nodes & References](Trees/TreeRepresentationWithNodesReferences.py) & [List of Lists](Trees/buildTreeTest.py)
+- [Tree Representations](Trees/): [Nodes & References](Trees/TreeRepresentationWithNodesReferences.py) & [List of Lists](Trees/BuildTreeTest.py)
 
 ---
 
@@ -144,7 +144,7 @@ Algorithms for arranging elements in order.
 - [Bubble Sort](Sorting/BubbleSortImple.py) - $O(n^2)$
 - [Selection Sort](Sorting/SelectionSortImple.py) - $O(n^2)$
 - [Insertion Sort](Sorting/InsertionSortImple.py) - $O(n^2)$
-- [Shell Sort](Sorting/ShellSortImple.py) - $O(n \log n)$
+- [Shell Sort](Sorting/ShellSortImple.py) - $O(n^2)$ worst case
 - [Merge Sort](Sorting/MergeSortImple.py) - $O(n \log n)$
 - [Quick Sort](Sorting/QuickSortImple.py) - $O(n \log n)$ average
 
@@ -168,7 +168,7 @@ Algorithms for graph traversal and pathfinding.
 
 ## ⚠️ Error Handling & Debugging
 
-- [Error and Exceptions](Error-debug/ErrorExceptions.py): Demonstrates `try`, `except`, `else`, and `finally` blocks for robust error handling.
+- [Error and Exceptions](ErrorHandling/ErrorExceptions.py): Demonstrates `try`, `except`, `else`, and `finally` blocks for robust error handling.
 
 ---
 
diff --git a/Stacks/BalanceParenthlessCheckImple.py b/Stacks/BalanceParenthesesCheckImple.py
similarity index 100%
rename from Stacks/BalanceParenthlessCheckImple.py
rename to Stacks/BalanceParenthesesCheckImple.py
diff --git a/Stacks/README.md b/Stacks/README.md
index e799a74..49cf122 100644
--- a/Stacks/README.md
+++ b/Stacks/README.md
@@ -4,5 +4,5 @@ This directory contains Python implementations of the Stack data structure and i
 
 ## Contents
 
-- [Stack Implementation](StackImple.py): Basic implementation of a LIFO (Last-In-First-Out) stack using a Python list. Includes `push`, `pop`, `peek`, `isEmpty`, and `size` methods.
-- [Balanced Parentheses Check](BalanceParenthlessCheckImple.py): Uses a stack to check if a string of opening and closing parentheses (round, square, and curly) is balanced.
+- [Stack Implementation](StackImple.py): Basic implementation of a LIFO (Last-In-First-Out) stack using a Python list. Includes `push`, `pop`, `peek`, `isEmpty`, and `size` methods. $O(1)$ operations.
+- [Balanced Parentheses Check](BalanceParenthesesCheckImple.py): Uses a stack to check if a string of opening and closing parentheses (round, square, and curly) is balanced. $O(n)$ time.
diff --git a/Trees/buildTreeTest.py b/Trees/BuildTreeTest.py
similarity index 100%
rename from Trees/buildTreeTest.py
rename to Trees/BuildTreeTest.py
diff --git a/Trees/README.md b/Trees/README.md
index 2047225..26fe98e 100644
--- a/Trees/README.md
+++ b/Trees/README.md
@@ -5,19 +5,19 @@ This directory contains Python implementations of various tree-based data struct
 ## Contents
 
 ### Binary Search Trees (BST)
-- [Binary Search Tree Implementation](BinarySearchTreesImple.py): A comprehensive implementation of a BST with `TreeNode` and `BinarySearchTree` classes, including insertion, deletion, and search.
+- [Binary Search Tree Implementation](BinarySearchTreesImple.py): A comprehensive implementation of a BST with `TreeNode` and `BinarySearchTree` classes, including insertion, deletion, and search. Average $O(\log n)$, worst case $O(n)$.
 - [Validate BST (Solution 1)](BinarySearchTreeCheckImpleSol1.py): Validates a BST by performing an in-order traversal and checking if the resulting values are sorted.
 - [Validate BST (Solution 2)](BinarySearchTreeCheckImpleSol2.py): Validates a BST by keeping track of the minimum and maximum allowable values for each node.
 - [Trim a BST](TrimBinarySearchTreeImple.py): Trims a BST so that all node values fall within a specified range $[min, max]$.
 
 ### Search Algorithms
-- [Binary Search (Iterative)](BinarySearchImple.py): Iterative implementation of the binary search algorithm on a sorted list.
-- [Binary Search (Recursive)](BinarySearchRecursiveImple.py): Recursive implementation of the binary search algorithm.
+- [Binary Search (Iterative)](BinarySearchImple.py): Iterative implementation of the binary search algorithm on a sorted list. $O(\log n)$.
+- [Binary Search (Recursive)](BinarySearchRecursiveImple.py): Recursive implementation of the binary search algorithm. $O(\log n)$.
 
 ### Heaps
 - [Binary Heap Implementation](BinaryHeapImple.py): Implements a min-heap using a recursive approach, including `insert`, `delMin`, and `buildHeap`.
 
 ### Tree Representations & Traversals
 - [Nodes and References Representation](TreeRepresentationWithNodesReferences.py): A simple implementation of a binary tree using a class-based nodes and references approach.
-- [List of Lists Representation](buildTreeTest.py): Demonstrates building and manipulating a tree using a "list of lists" approach.
+- [List of Lists Representation](BuildTreeTest.py): Demonstrates building and manipulating a tree using a "list of lists" approach.
 - [Tree Level Order Print](TreeLevelOrderPrintImple.py): Prints a binary tree in level order (breadth-first) using a queue, with each level on a new line.