• Basic Data Structures and problems - Java Implementation.

• List of solved problems:

• Arrays:

  • Basic Implementation of Arrays
  • Comparing arrays
  • Contains any duplicate using: [Map] [Set]
  • Equilibrium Index
  • Find Duplicate Number
  • Find Min and Max
  • k largest(or smallest) elements in an array: Algorithms
  • Find Missing Number using: [Formula] [XOR]
  • Find Non Repeating Number
  • Find Two Numbers Summing To Target: [Brute Force] [Binary Search] [Collection]
  • Find Intersection: [Unsorted chars] [Sorted numbers] [Map]
  • Remove Duplicates
  • Remove target number and return new length
  • Reverse: [Recursion] [Reverse individual words]
  • Rotate array using: [Buffer] [Bubble rotate] [Reversal algorithm]
  • Random Shuffle
  • MoveZerosToEnd
  • AddOneToArray
  • Matrix:
    • 2D Array
    • Search key in Row wise Column wise sorted matrix
    • Count negative numbers in Row wise Column wise sorted matrix
    • Print Spiral Pattern
    • Print Pattern
    • Set 0's in Row and Column
    • Rotate Matrix Anticlockwise
    • Find Islands Using DFS
  • BasicOperations

• HashMap and Hashtable:

  • IterateHashMap
  • Map Sort (Sort by Value)
  • Notes:
    • Working of HashMap
    • HashMap vs Hashtable
    • ConcurrentHashMap vs SynchronizedHashMap
    • BasicOperations

• Binary tree:

  • Node
  • Add node using:
    • Iterative method
    • Recursion
  • Delete Tree
  • Least Common Ancestor
  • Sum of all Node's data
  • Traversals: Source
  • Check if a binary tree is BST or not

• Linked list:

  • Node
  • Add Node
  • Add Node to Sorted List
  • Delete Node
  • Detect Loop and return starting node in Singly List - Floyd’s Algorithm
  • Reverse Linked List:
    • Reverse Entire Linked List
    • Reverse List From Midpoint
    • Reverse List In Groups
    • Reverse List Using Recursion
  • Remove Duplicates from an Unsorted Linked list using:
    • HashMap
    • Two pointer technique
  • Find n’th node from the end of a Linked List:
    • Using length of linked list
    • Two pointer technique

• Queue:

  • Priority Queue Chars
  • Priority Queue Min
  • Priority Queue Max - reversing the sorting order
  • Interview question (solved using Comparable Interface)
  • QueueUsingStack

• Stack:

  • Stack Using Linked List
  • Stack Using Array
  • Two stacks in One array
  • Three stacks in One array
  • Valid Parentheses
  • Valid Pop Sequence

• Collections (most used):

  • List: ArrayList, LinkedList
  • Set: HashSet, TreeSet, LinkedHashSet
  • Map: HashMap, Hashtable, LinkedHashMap, TreeMap
  • Queue: PriorityQueue
  • Stack
  • Arrays and Collections Class
  • Concurrency package for all collections