1: Queue using Stacks 2: Stack using Queues 3: Find Minimum value in Stack in O(1) time 4: Sort a Stack using 1 Extra Stack 5: Find Middle/ Delete Middle Element of Stack in O(1) time. 6: Single Array as K stacks. Not fixed size.

1: Anagrams 2: Palindrome 3: Reverese Words in Sentence String 4: String Interleaved of 2 other Strings 5: Strtok 6: Strings Rotated version of each other 7: Remove 'b' and 'ac' patterns from string in place and in one given pass. O(n) solution. 8: Remove Duplicate Characters in string in place. O(n). No extra space allowed. 9: RLE Algorithm

1: Find first repeating element in array of integers. 2: Find smallest positive integer that cannot be represented as a sum of any subset of given array. 3: Re-arrange alternate positive negative numbers with O(1) space 4: Search in almost sorted array 5: Maximum sum path across 2 sorted arrays 6: Find Next number with same set of digits 7: Create Matrix alternate 'X' and '0' 8: Smallest Subarray with sum greater than given value 9: Find Subarray given a sum 10: Find Subarray with sum equal to Zero 11: Count distinct pairs with difference equal to k 12: Find Minimum in sorted and rotated array 13: Print all combinations of R elements in array of size N 14: Sort Elements by Frequency 15: Maximum difference between two elements such that larger element appears after smaller element

1: Delete a Node in Doubly Linked List 2: Delete a Node which have greater values on right side. 3: Flatten Multi-level linked list 4: Memory Efficient Doubly Linked List 5: Find Triplet from 3 different linked list which is equal to given sum 6: Intersection Point of 2 linked lists 7: Print Middle Element of Linked List 8: Check if linked list is a Palindrome 9: Get nth node from end of linked list 10: Alternating Split 11: Intersection of 2 different sorted linked list 12: Merge Linked List at Alternate Positions 13: Pair wise swap elements of linked list 14: Partition a Linked List 15: Remove duplicates from un-sorted linked list 16: Reverse alternate K nodes 17: Reverse Doubly Linked List 18: Rotate Linked List to K Nodes 19: Segregate odd and even numbers in linked list maintaining the order 20: Split circular linked list 21: Union and Intersection of Linked List

1: Delete a BST 2: Deleting a Node in BST 3: Iterative InOrder Traversal of BT 4: Iterative Post Order Traversal of BT 5: Reverse Level Order Traversal of BT 6: Iterative Method find height of BT 7: Maximum width of BT 8: Check if BT is height balanced. 9: Check if BT is sum tree. 10:Check if Each Internal Node of BST has exactly One Child given Pre-Order 11:Find if triplet in Balanced BST which Adds to Zero 12:Find Inorder successor for given node of BST 13:InOrder successor for all nodes of given BST 14:Validate if BST 15:Largest BST in BT 16:Check if there is a root to leaf node path whose sum equal to given number. 17:Check if two trees are Isomorphic 18:Find Lowest Common Ancestor in BST 19:Convert Binary Tree to Binary Search Tree 20:Convert Binary Tree to Doubly Linked List 21:Convert Linked List to Complete Binary Tree 22:Convert Binary Search Tree to Binary Tree such that sum of all greater keys is added to given node's value 23:Convert Binary Tree to its Sum Tree 24:Merge two balanced BST 25:Find maximum sum from root to leaf node and print the path. 26:Print Left View of Binary Tree 27:Print Nodes a distance K from Root of Binary Tree 28:Recursively Print Ancestors of a given Node in Binary Tree 29:Maximum Difference Between Node and its Ancestor in Binary Tree.

1: Breadth First Traversal 2: Depth First Traversal 3: Topological Sorting 4: Find if path between two points in graph

1: Find Missing Element in Arithmetic Progression 2: Permutation of a Number - Recursive and Iterative - Check it later !!! 3: Get longest Sequence in Circular Q, with same number as starting and ending point at different indexes. 4: Find Smallest Windows of keys in a given array. 5: Minimum n elements from given stream of data. 6: Design Data Structure with 0(1) operation 7: Print Employee Hierarchy based on relationship given between them 8: Rearrange Numbers in list to create maximum number 9: Find Minimum distance between given pair of words in a string sentence. 10:Forward Permutations of string 11:Find Common Manager of Two Employees 12:Find 'i'th most popular item sold on Amazon 13:Check if path exists in Matrix Puzzle of 0's and 1's 14:Generate Palindrome From String if Possible.