[07 Feb 2020] Interview Question for Data Structure and Algorithm in Java

Table of Contents [hide]

• Stack
  • Question 1:  Implement a stack using array.
  • Question 2: Implement a stack using Linked List.
  • Question 3:  Implement a stack using two queues.
  • Question 4 : Sort an stack using another stack
• Queue
  • Question 5:  Implement Queue using Array in java.
  • Question 6:  Implement a stack using two queues .
• Linked List
  • Question 7 : Implement singly linked list in java.
  • Question 8: How to reverse linked list in java.
  • Question 9: How to find middle element of linked list.
  • Question 10 : How to find nth element from end of linked list .
  • Question 11 : How to detect a loop in linked list. If linked list has loop, find the start node for the loop.
  • Question 12: How to check if linked list is palindrome or not?
  • Question 13 :  Find intersection of two linked lists?
  • Question 14 :  How to reverse a linked list in pairs?
  • Question 15 :  Implement Doubly linked list in java?
• Array
  • Question 16 : Write java Program to Find Smallest and Largest Element in an Array.
  • Question 17 : Find missing number in the array.
  • Question 18 : Search an element in rotated and sorted array.
  • Question 19 : Find minimum element in a sorted and rotated array.
  • Question 20: Find second largest number in an array
  • Question 21 : Find the number occurring odd number of times in an array
  • Question 22 : Find minimum number of platforms required for railway station
  • Question 23 : Find a Pair Whose Sum is Closest to zero in Array
  • Question 24 : Given a sorted array and a number x, find the pair in array whose sum is closest to x
  • Question 25 : Find all pairs of elements from an array whose sum is equal to given number
  • Question 26: Given an array of 0’s and 1’s in random order, you need to separate 0’s and 1’s in an array.
  • Question 27 : Separate odd and even numbers in an array
  • Question 28 : Given an array containing zeroes, ones and twos only. Write a function to sort the given array in O(n) time complexity.
  • Question 29 : Find local minima in array
  • Question 30 : Sliding window maximum in java
  • Question 31 : Count number of occurrences (or frequency) of each element in a sorted array
  • Question 32 : Find subarrays with given sum in an array.
  • Question 33 : Find peak element in the array.
  • Question 34 : Find leaders in an array.
  • Question 35 : Count 1’s in sorted Binary Array.
  • Question 36 : Find first repeating element in an array of integers.
  • Question 37 : Check if Array Elements are Consecutive.
  • Question 38 : Permutations of array in java.
  • Question 39 : Rotate an array by K positions.
  • Question 40 : Stock Buy Sell to Maximize Profit.
  • Question 41 : Find maximum difference between two elements such that larger element appears after the smaller number.
  • Question 42 : Search in a row wise and column wise sorted matrix.
  • Question 43 : Largest sum contiguous subarray.
  • Question 44 : Find the Contiguous Subarray with Sum to a Given Value in an array.
  • Question 45 : Longest Common Prefix in an array of Strings in java.
  • Question 46 : Find all subsets of set (power set) in java.
• String
  • Question 47 : How to reverse a String in java? Can you write a program without using any java inbuilt methods?
  • Question 48 : Write a java program to check if two Strings are anagram in java?
  • Question 49 : Write a program to check if String has all unique characters in java?
  • Question 50 : How to check if one String is rotation of another String in java?
  • Question 51 : How to find duplicate characters in String in java?
  • Question 52 : Find first non repeated character in String in java?
  • Question 53 : Find all substrings of String in java?
  • Question 54 : Find length of String without using any inbuilt method in java?
  • Question 55 : Write a program to print all permutations of String in java?
• Binary Tree
  • Question 56 : How can you traverse binary tree?
  • Question 57 : Write an algorithm to do level order traversal of binary tree?
  • Question 58 :  Write an algorithm to do spiral order traversal of binary tree?
  • Question 59 : How can you print leaf nodes of binary tree?
  • Question 60 : How to count leaf nodes of binary tree.
  • Question 61 : How to print all paths from root to leaf in binary tree.
  • Question 62 : How to find level of node in binary tree
  • Question 63 : How to find maximum element in binary tree.
  • Question 64 : How to find lowest common ancestor(LCA) in binary tree.
  • Question 65 : How to do boundary traversal of binary tree.
  • Question 66 : How to print vertical sum of binary tree?
  • Question 67 : Count subtrees with Sum equal to target in binary tree?
• Binary Search tree
  • Question 68 : What is binary search tree?
  • Question 69 : Can you write algorithm to insert a node in binary search tree.
  • Question 70 : Can you write algorithm to delete a node in binary search tree.
  • Question 71 :  How can you find minimum and maximum elements in binary search tree?
  • Question 72 : How to find lowest common ancestor(LCA) in binary search tree.
  • Question 73 : Find inorder successor in a Binary search Tree
  • Question 74 : Convert sorted array to balanced BST
  • Question 75 : Convert sorted Linked List to balanced BST
  • Question 76 : Check if a binary tree is binary search tree or not in java
• Sorting
  • Question 77 : Write an algorithm to implement bubble sort?
  • Question 78 : Write an algorithm to implement insertion sort sort?
  • Question 79 : Write an algorithm to implement selection sort sort?
  • Question 80 : Can you write algorithm for merge sort and also do you know complexity of merge sort?
  • Question 81 : Do you know how to implement Heap sort?
  • Question 82 : Implement quick sort in java?
  • Question 83 : Implement shell sort in java?
  • Question 84 : Implement Counting sort in java?
  • Question 85 : What is binary search? Can you write an algorithm to find an element in sorted array using binary search?
• Graph
  • Question 86 : Write algorithm to do depth first search in a graph.
  • Question 87 : Write algorithm to do breadth first search in a graph.
  • Question 88 : Explain Dijkstra algorithm from source to all other vertices.
  • Question 89 : Explain Bellman Ford algorithm to find shortest distance
  • Question 90 : Explain Kruskal’s algorithm for finding minimum spanning tree
• Dynamic Programming
  • Question 91 : Given two String, find longest common substring.
  • Question 92 : Given two Strings A and B. Find the length of the Longest Common Subsequence (LCS) of the given Strings.
  • Question 93 : Given a matrix, we need to count all paths from top left to bottom right of MxN matrix. You can either move down or right.
  • Question 94 : Edit Distance Problem in java
  • Question 95: Coin change problem in java
  • Question 96 : Minimum number of jumps to reach last index
• Miscellaneous
  • Question 97 : What is an algorithm and how to calculate complexity of algorithms.
  • Question 98 : Implement trie data structure in java.
  • Question 99 : Count Factorial Trailing Zeroes in java.
  • Question 100 : Largest Rectangular Area in a Histogram.
  • Question 101 : Check for balanced parentheses in an expression in java.
  • Question 102 : What is Memoization.