Algorithm - Interview Questions and Answers for 'Algorithm' | Search Interview Question - javasearch.buggybread.com

Javasearch.buggybread.com

Search Interview Questions

More than 3000 questions in repository.

There are more than 900 unanswered questions.
Click here and help us by providing the answer.

Have a video suggestion.
Click Correct / Improve and please let us know.

Submit Question

Algorithm - Interview Questions and Answers for 'Algorithm' - 62 question(s) found - Order By Newest

next 30

Advanced level question frequently asked in US based companies. Recently asked in EMC and Intuit.

Q1. Can you provide some implementation of a Dictionary having large number of words ?

Ans. Simplest implementation we can have is a List wherein we can place ordered words and hence can perform Binary Search.

Other implementation with better search performance is to use HashMap with key as first character of the word and value as a LinkedList.

Further level up, we can have linked Hashmaps like ,

hashmap {
a ( key ) -> hashmap (key-aa , value (hashmap(key-aaa,value)
b ( key ) -> hashmap (key-ba , value (hashmap(key-baa,value)
....................................................................................
z( key ) -> hashmap (key-za , value (hashmap(key-zaa,value)
}

upto n levels ( where n is the average size of the word in dictionary.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java collections hashmap binary search search algorithm advanced architecture data structure Asked in 6 Companies frequent}

Try 1 Question(s) Test

Q2. In a Linked list with sorted numbers, insert a new numbers while maintaining the sort order.

Ans.
public class LinkedList {

   Node start = null;
   Node head = null;

   class Node{
      Integer body;
      Node nextNode;

      Node(Integer value){
         body = value;
      }
   }

   private void insertInMiddle(Integer value){
      head = start;
      if(start == null) {
         start = new Node(value);
         head = start;
         head.nextNode = null;
         return;
      }

      while(head.body < value){
         if(head.nextNode == null || head.nextNode.body >= value){
            Node newNode = new Node(value);
            newNode.nextNode = head.nextNode;
            head.nextNode = newNode;

            break;
         }
         head = head.nextNode;
      }
   }

   private void traverse(){
      head = start;
      while(head != null){
         System.out.println(head.body);
         head = head.nextNode;
      }
   }

   public static void main(String[] args){
      LinkedList ll = new LinkedList();

      ll.insertInMiddle(5);
      ll.insertInMiddle(10);
      ll.insertInMiddle(15);
      ll.insertInMiddle(7);

      ll.traverse();

   }
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve LinkedList Data structures Algorithm}

Q3. What is the difference between Graph's Breadth first and Depth First algorithm ?

Ans. In Breadth first algorithm, all the adjacent nodes of the starting node is visited first and then the same rule is followed while moving inwards whereas

In Depth first algorithm, all the nodes of a single traversal path are visited first till a cycle or an end is found.

For example , given the following entries of adjacent nodes

1,2
1,3
1,6
2,4
2,5
3,6

The Breadth first path would be

1,2,3,6,4,5

and Depth first path would be

1,2,4,5,3,6

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve graph traversal breadth first vs depth first frequent}

Q4. What are the pre-requisite for the collection to perform Binary Search ?

Ans. 1. Collection should have an index for random access.
2. Collection should have ordered elements.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java collections search algorithm search binary search at&t intermediate}

Q5. Write an algorithm / Java Program to show duplicates in an array of n elements?

Ans. int duplicateArray[] = { 1, 2, 2, 3, 4, 5, 6, 8, 9}
Set unique = new HashSet();
for (int i = 0; i < duplicateArray.length; i) {
if (unique.contains(duplicateArray[i])) {
System.out.println(duplicateArray[i]);
} else {
unique.add(duplicateArray[i]);
}
}

Complexity O(n) = nHashSet contains and add has O(n) = 1

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve coding code Asked in 2 Companies}

Q6. What is a binary tree ?

Ans. Binary tree is a tree in which each node has up to two children.Tree is a data structure composed of nodes.Each tree has a root node(not necessary in graph theory). The root node has zero or more child nodes.Each child node has zero or more child nodes, and so on.The tree cannot contain cycles.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve binary tree Asked in 1 Companies}

Q7. Write a program for LinkedList, with method to append node and traversing the list ?

Ans. public class LinkedList {

   Node start = null;
   Node head = null;

   class Node {
      Integer body;
      Node nextNode;

      Node(Integer value) {
         body = value;
      }
   }

   private void addNodeToEnd(Integer value) {
      if (start == null) {
         start = new Node(value);
         head = start;
         head.nextNode = null;
         return;
      }

      while (head.nextNode != null) {
         head = head.nextNode;
      }

      head.nextNode = new Node(value);
   }

   private void traverse() {
      head = start;
      while (head != null) {
         System.out.println(head.body);
         head = head.nextNode;
      }
   }

   public static void main(String[] args) {
      LinkedList ll = new LinkedList();

      ll.addNodeToEnd(5);
      ll.addNodeToEnd(10);
      ll.addNodeToEnd(15);

      ll.traverse();

   }
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve LinkedList Data structures Algorithm}

Q8. Write a Program for Graph Depth First Traversal using Apache Commons MultiMap

Ans. import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;

public class Graph {
   private static Multimap<Integer,Integer> adjacentDirectedNodesMap = ArrayListMultimap.create();
   private static Set<Integer> alreadyVisited = new HashSet();

   static{
      adjacentDirectedNodesMap.put(1, 2);
      adjacentDirectedNodesMap.put(1, 3);
      adjacentDirectedNodesMap.put(1, 5);
      adjacentDirectedNodesMap.put(2, 4);
      adjacentDirectedNodesMap.put(4, 5);
   }

   public static void main(String[] args){
      ArrayList visited = new ArrayList();

      Integer startNode = 1;

      displayAdjacentNodes(startNode);

   }

   private static void displayAdjacentNodes(Integer integer){
      if(alreadyVisited.contains(integer)){
         return;
      }
      alreadyVisited.add(integer);
      System.out.println(integer);
      for(Integer adjacentNodes: adjacentDirectedNodesMap.get(integer)){
         displayAdjacentNodes(adjacentNodes);
      }
   }

}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve graph traversal depth first algorithm}

Q9. Which sorting algorithm is used by Collections.sort() in Java ?

Ans. The sorting algorithm is a modified mergesort. This algorithm offers guaranteed n log(n) performance.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java algorithm collections collections.sort sorting algorithm expert}

Try 1 Question(s) Test

Q10. How to determine if the linked list has a cycle in it ?

Ans. http://stackoverflow.com/questions/494830/how-to-determine-if-a-linked-list-has-a-cycle-using-only-two-memory-locations

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve linked list data structure algorithm java ebay}

Q11. Find the repeating number using O(n) time and constant space.

Ans. http://www.geeksforgeeks.org/find-duplicates-in-on-time-and-constant-extra-space/

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve algorithm program code coding makemytrip.com}

Q12. Explain Travelling SalesMan Problem ?

Ans. https://en.wikipedia.org/wiki/Travelling_salesman_problem

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q13. Write an Algorithm for Graph Traversal ? The Graph has a loop.

Ans. Please not that all such questions can be easily answered through recursion.

Simple recursive implementation could be

traverse(root);

void traverse(Element element){
if(element.hasNext()){
traverse(element.next());
} else {
System.out.println(element);
}
}

but this algo / code lead to endless loop if there is a loop in graph traversal.

So you can keep a collection to keep track of which elements have laready been traversed

static List<Elements> listOfAlreadyTraversedElements = new ArrayList<Elements>();

main(){
traverse(root);
}

void traverse(Element element){
if(element.hasNext()){
traverse(element.next());
} else {
listOfAlreadyTraversedElements.add(element);
System.out.println(element);
}
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve graph traversal algorithm graph traversal algorithm using recursion Asked in 1 Companies intermediate}

Q14. Flatten a Binary Tree to Linked List

Ans. https://www.geeksforgeeks.org/flatten-a-binary-tree-into-linked-list/

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q15. Explain various Searching and Sorting Algorithms ?

^{This question was recently asked at 'HeadStrong,ServiceNow'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Search Algorithm Sorting Algorithm Asked in 2 Companies basic frequent}

Q16. Write an algorithm / java program for Heap Sort ?

Ans. https://www.geeksforgeeks.org/heap-sort/

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve sorting heap sort Asked in 1 Companies frequent}

Q17. Write any sorting algorithm.

Ans. https://javasearch.buggybread.com/InterviewQuestions/questionSearch.php?searchOption=label'

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Algorithm Sorting Algorithm Asked in 4 Companies basic frequent}

Q18. How to create list that will sort it's elements dynamically?

Ans. Override the behavior of collection class to sort the list upon each element addition. Though it's not recommended as list are sorting heavy data structures.

List<MyType> list = new ArrayList<MyType>() {
public boolean add(MyType mt) {
super.add(mt);
Collections.sort(list, comparator);
return true;
}
};

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies intermediate}

Q19. Write program to create a linked list and perform different operations on it.

Ans. import java.util.*;
class LinkedListSolution{
protected LinkedList list;
public LinkedListSolution(){
list = new LinkedList();
}
public Object pop() throws NoSuchElementException{
if(list.isEmpty())
throw new NoSuchElementException();
else
return list.removeFirst();
}
public void push(Object obj){
list.addFirst(obj);
}
public Object peek() throws NoSuchElementException{
if(list.isEmpty())
throw new NoSuchElementException();
else
return list.getFirst();
}
public boolean isEmpty(){
return list.isEmpty();
}
public String toString(){
return list.toString();
}
}
class TestStack{
public static void main(String args[]){
LinkedListSolution s = new LinkedListSolution();
s.push("First");
s.push("Second");
s.push("Third");
System.out.println("Top: " s.peek());
s.push("Fourth");
while(!(s.isEmpty()))
System.out.println(s.pop());
}
}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Linkedlist data structures algorithm Asked in 2 Companies basic}

Q20. Explain bubble sort.

Ans. array is traversed from first element to last element. Here current element is compared with next element. If current element is greater than next element it is swapped.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve sorting bubble sort Asked in 1 Companies}

Q21. Write code to check if a Binary tree is symmetrical

^{This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve binary tree Asked in 1 Companies}

Q22. Write a function that returns the depth of a tree.

^{This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q23. Write code to find the node where two linked lists intersect.

^{This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q24. Check if tic tac toe has a winner

^{This question was recently asked at 'Microsoft'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q25. Write program to balance a binary tree

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve}

Q26. Given a graph, find if it represents a tree

Ans. We can simply find it by checking the criteria of a tree. A tree will not contain a cycle, so if there is any cycle in the graph, it is not a tree. We can check it using another approach, if the graph is connected and it has V-1 edges, it could be a tree. Here V is the number of vertices in the graph

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q27. Explain different sorting algorithms and Big O of each

^{This question was recently asked at 'Microsoft,ServiceNow'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 2 Companies}

Q28. Write a program to find loop in a linked list

^{This question was recently asked at 'Microsoft'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q29. How to convert a bst to doubly linked list

^{This question was recently asked at 'Amazon'.This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve Asked in 1 Companies}

Q30. How do we implement a weight round robin algorithm in load balancing ?

^{This question is still unanswered. Can you please provide an answer.}

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve load balancing load balancer}

next 30