Create READMEs for all subdirectories

Arrays/README.md

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+# Arrays
+
+This directory contains implementations and problems related to Arrays.
+
+## Contents
+
+### Anagram Check
+Checks if two strings are anagrams of each other.
+- **Files**: [Anagram_Check_Sorted_Sol.py](Anagram_Check_Sorted_Sol.py), [Anagram_Check_manual_Sol.py](Anagram_Check_manual_Sol.py)
+
+### Array Pair Sum
+Given an integer array, output all unique pairs that sum up to a specific value `k`.
+- **File**: [ArrayPairSumSol.py](ArrayPairSumSol.py)
+
+### Find Missing Element
+Find the missing element in a shuffled second array.
+- **Files**: [ArrayFindTheMissingElement_XOR_sol.py](ArrayFindTheMissingElement_XOR_sol.py), [ArrayFindTheMissingElement_brute_force_sol.py](ArrayFindTheMissingElement_brute_force_sol.py), [ArrayFindTheMissingElement_hash_table_sol.py](ArrayFindTheMissingElement_hash_table_sol.py), [ArrayFindTheMissingElement_takingSumandSubtract_sol.py](ArrayFindTheMissingElement_takingSumandSubtract_sol.py)

Error-debug/README.md

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+# Error Handling
+
+This directory demonstrates error handling techniques in Python.
+
+## Contents
+
+### Basic Exception Handling
+Demonstrates `try-except-else-finally` blocks and user input validation.
+- **File**: [ErrorExceptions.py](ErrorExceptions.py)

GraphAlgorithms/README.md

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+# Graph Algorithms
+
+This directory contains implementations of various Graph Algorithms.
+
+## Contents
+
+### Adjacency List Implementation
+- **File**: [AdjacencyListGraphImple.py](AdjacencyListGraphImple.py)
+
+### Breadth First Search (BFS) - Word Ladder Problem
+- **Files**: [BFS.py](BFS.py), [WordLadderProblem.py](WordLadderProblem.py)
+
+### Depth First Search (DFS) - Knight's Tour Problem
+- **Files**: [DFSImpleTheKnightsTourProblem.py](DFSImpleTheKnightsTourProblem.py), [TheKnightsTourProblem.py](TheKnightsTourProblem.py)
+
+### General DFS
+A more general implementation of Depth First Search.
+- **File**: [DFSGeneral.py](DFSGeneral.py)

LinkedLists/README.md

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+# Linked Lists
+
+This directory contains implementations and problems related to Linked Lists.
+
+## Contents
+
+### Singly Linked List Implementation
+Basic skeleton for a Singly Linked List.
+- **File**: [SingleLinkedListImple.py](SingleLinkedListImple.py)
+
+### Doubly Linked List Implementation
+Basic skeleton for a Doubly Linked List.
+- **File**: [DoublyLinkedListImple.py](DoublyLinkedListImple.py)
+
+### Singly Linked List Cycle Check
+Check if a singly linked list contains a cycle using the "two runners" (slow and fast pointers) strategy.
+- **File**: [SinglyLinkedListCycleCheckImple.py](SinglyLinkedListCycleCheckImple.py)
+
+### Reverse a Linked List
+Reverse a linked list in-place.
+- **File**: [LinkedListReversal.py](LinkedListReversal.py)
+
+### Nth to Last Node
+Find the nth to last node in a linked list.
+- **File**: [LinkedListNthToLastNode.py](LinkedListNthToLastNode.py)

Queues/README.md

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+# Queues
+
+This directory contains implementations of Queues.
+
+## Contents
+
+### Queue Implementation
+Basic queue operations (FIFO): `enqueue`, `dequeue`, `isEmpty`, `size`.
+- **File**: [QueueImple.py](QueueImple.py)
+
+### Queue with Two Stacks
+Implement a queue using two stacks.
+- **File**: [QueueWith2StacksImple.py](QueueWith2StacksImple.py)

Recursion/README.md

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+# Recursion
+
+This directory contains implementations and problems related to Recursion.
+
+## Contents
+
+### Cumulative Sum
+Compute the cumulative sum from 0 to `n`.
+- **File**: [RecursionCumulativeSum.py](RecursionCumulativeSum.py)
+
+### Sum of Digits
+Returns the sum of all individual digits in an integer.
+- **File**: [RecursionSumOfDigits.py](RecursionSumOfDigits.py)
+
+### Word Split
+Determine if a string can be split into words found in a given list.
+- **File**: [RecursionWordSplit.py](RecursionWordSplit.py)
+
+### Reverse a String
+Recursive implementation to reverse a string.
+- **File**: [RecursionReverseStr.py](RecursionReverseStr.py)
+
+### String Permutations
+Output all possible permutations of a string.
+- **File**: [RecursionStrPermutation.py](RecursionStrPermutation.py)
+
+### Fibonacci Sequence
+Implementations using iteration, recursion, and dynamic programming (memoization).
+- **Files**: [FibonacciSeqIterative.py](FibonacciSeqIterative.py), [FibonacciSeqRecursion.py](FibonacciSeqRecursion.py), [FibonacciSeqDynamic.py](FibonacciSeqDynamic.py)
+
+### Coin Change Problem
+Find the fewest coins needed to make a change amount.
+- **Files**: [CoinChangeProblemRecursion.py](CoinChangeProblemRecursion.py), [CoinChangeProblemDynamic.py](CoinChangeProblemDynamic.py)

Sorting/README.md

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+# Sorting
+
+This directory contains implementations of various Sorting Algorithms.
+
+## Contents
+
+### Bubble Sort
+- **File**: [BubbleSortImple.py](BubbleSortImple.py)
+- **Complexity**: $O(n^2)$ worst and average case, $O(n)$ best case.
+
+### Selection Sort
+- **File**: [SelectionSortImple.py](SelectionSortImple.py)
+- **Complexity**: $O(n^2)$ for all cases.
+
+### Insertion Sort
+- **File**: [InsertionSortImple.py](InsertionSortImple.py)
+- **Complexity**: $O(n^2)$ worst and average case, $O(n)$ best case.
+
+### Merge Sort
+- **File**: [MergeSortImple.py](MergeSortImple.py)
+- **Complexity**: $O(n \log n)$ for all cases.
+
+### Quick Sort
+- **File**: [QuickSortImple.py](QuickSortImple.py)
+- **Complexity**: $O(n^2)$ worst case, $O(n \log n)$ average/best case.
+
+### Shell Sort
+- **File**: [ShellSortImple.py](ShellSortImple.py)
+- **Complexity**: Between $O(n)$ and $O(n^2)$ depending on increment sequence.

Stacks/README.md

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+# Stacks
+
+This directory contains implementations and problems related to Stacks.
+
+## Contents
+
+### Stack Implementation
+Basic stack operations (LIFO): `push`, `pop`, `peek`, `isEmpty`, `size`.
+- **File**: [StackImple.py](StackImple.py)
+
+### Balanced Parentheses Check
+Check if a string of opening and closing parentheses is balanced.
+- **File**: [BalanceParenthlessCheckImple.py](BalanceParenthlessCheckImple.py)

Trees/README.md

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+# Trees
+
+This directory contains implementations and problems related to Trees.
+
+## Contents
+
+### Binary Search Tree Implementation
+- **File**: [BinarySearchTreesImple.py](BinarySearchTreesImple.py)
+
+### Binary Heap Implementation
+- **File**: [BinaryHeapImple.py](BinaryHeapImple.py)
+
+### Binary Search
+Recursive and iterative implementations.
+- **Files**: [BinarySearchImple.py](BinarySearchImple.py), [BinarySearchRecursiveImple.py](BinarySearchRecursiveImple.py)
+
+### Validate BST
+Check if a binary tree is a valid Binary Search Tree.
+- **Files**: [BinarySearchTreeCheckImpleSol1.py](BinarySearchTreeCheckImpleSol1.py), [BinarySearchTreeCheckImpleSol2.py](BinarySearchTreeCheckImpleSol2.py)
+
+### Trim a BST
+Trim a BST so all nodes are within a given range `[min, max]`.
+- **File**: [TrimBinarySearchTreeImple.py](TrimBinarySearchTreeImple.py)
+
+### Tree Representation (Nodes & References)
+Implementing a tree using classes and references.
+- **File**: [TreeRepresentationWithNodesReferences.py](TreeRepresentationWithNodesReferences.py)
+
+### Tree Level Order Print
+Print a binary tree in level order.
+- **File**: [TreeLevelOrderPrintImple.py](TreeLevelOrderPrintImple.py)
+
+### Build Tree Test
+Build a tree and fetch nodes and insert using list of lists.
+- **File**: [buildTreeTest.py](buildTreeTest.py)

deque/README.md

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+# Deque
+
+This directory contains an implementation of Deque (Double-ended queue).
+
+## Contents
+
+### Deque Implementation
+Double-ended queue operations: `addFront`, `addRear`, `removeFront`, `removeRear`, `isEmpty`, `size`.
+- **File**: [DequeImple.py](DequeImple.py)