Array Sorting Algorithms

• Bubble sort algorithm 
• Selection sort algorithm 
• Insertion sort algorithm
• Merge sort algorithm
• Quick sort algorithm

Array Interview Questions

• Find a missing number in an array of distinct integers
• Find a number occurring odd number of times in array
• Dutch national flag problem
• Classify or segregate array containing even & odd numbers
• Sort an integer array containing 0 & 1
• Check if array contains duplicate elements
• Move zeros to end of array
• Reverse an integer array
• Replace every element in array by greatest number on its right
• Find maximum & minimum element in array
• Initialize & loop one, two, three dimensional array
• Create or implement stack using array
• Implement two stacks using single array
• Find missing number from array
• Second smallest element in an array of integers
• Second largest element in an array of integers
• Find maximum sum subarray using Kadane’s algorithm
• Prime number generation using Sieve of Eratosthenes algorithm
• Union of two sorted arrays
• Intersection of two sorted arrays
• Leader element in integer array
• Majority element in integer array (Boyer Moore’s voting algorithm)
• Search element in sorted array
• Find element in an array using binary search algorithm
• Running sum of 1d array

Single LinkedList Interview Questions

• Insert node to sorted singly linked list
• Find number of times given element exists in single linked list
• Delete  all nodes of a single linked list
• Remove duplicate nodes from sorted singly linked list
• Reverse single linked list
• Reverse singly linked List in pairs
• Print single linked list in a reverse order
• Implement stack using single linked list
• Find midpoint node of single linked list
• Find nth node from end in a single linked list
• Find Intersection point of two single linked lists
• Floyd’s cycle detection algorithm to check loop in single linked list
• Merge two sorted singly linked lists

Binary Tree Interview Questions

Level Order Traversal or Breadth First Search (BFS):

• Binary tree traversal 
• Find level in binary tree having maximum sum
• Sum of nodes in binary tree
• Height of binary tree
• Size of binary tree 
• Count non-leaf nodes (left & right child) in binary tree
• Count non leaf nodes having one child node
• Count non leaf nodes in binary tree
• Find number of leaf nodes in a binary tree
• Maximum or largest element in a binary tree
• Check leaf nodes of binary tree are at same level
• Find level of given node in binary tree
• Find maximum width of binary tree
• Spiral or Zigzag binary tree traversal
• Print binary tree in reverse order

Depth First Search Algorithm:

• Binary tree traversal algorithm
• Size of binary tree
• Diameter of binary tree
• Minimum & maximum element in binary tree
• Height of binary tree in java
• Delete all nodes of a binary tree
• Find root to leaf path sum equals given number binary tree
• Find maximum sum in root to leaf path in binary tree
• Vertical order traversal of binary tree
• Find vertical order sum in a binary tree
• Connect nodes at same level in a binary tree
• LCA (Lowest common ancestor) in a binary tree
• Print ancestors of node in a binary tree
• Print paths from root to leaf nodes in binary tree
• Print nodes at k distance from root in binary tree
• Print nodes K distance from leaf nodes in a binary tree
• Check two binary trees are equal
• Isomorphic binary tree
• Quasi-Isomorphic binary trees
• Mirror or symmetric binary tree
• Convert binary tree to mirror/symmetric tree

Binary Search Tree Interview Questions

• Minimum and maximum value in binary search tree
• Search node in a binary search tree
• Delete node from binary search tree
• Check given binary tree is a binary search tree
• Ceil value of input data in binary search tree
• Floor value of input data in Binary search tree
• Find lowest common ancestor (LCA) in binary search tree
• Find K smallest element in binary search tree
• Print binary search tree for given range K1 & K2
• InOrder predecessor of a node in BST
• InOrder successor of a node in BST