# House Joy, Bangalore Interview Experience for Backend Developer

Experience: More than 1.5 years

Round 1: Written Test, I have to complete 3 code and 2 SQL in 45 minutes.

a. You are climbing a staircase. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

b. s = “aAAbbbb”; s1 = “aA”   , Here a and A are different . So basically you have to return the total number of characters present in String s available in string s1.  a->1, A->2, ..total = 1+2 = 3;

c. given array, You have to return the count of duplicate value x, arr[] = {1, 2, 2, 2, 2, 2, 23,,4, 5, 5, 5}  ; x = 2 ; result 2->5;

d.write SQL queries to update the column value, changing the value of sex (male to female, female to male);

e.sql query, return the table where the population is greater than 2.5 m and the population of the state is 5m.

Round 2: Technical Round 1

Started with Data Structure and Linked List

First question he asked me: a. Given the linked list, u have to reverse the linked list in pairwise. eg. 1->2->3->4->5     , return  4->5 ->3 ->4->1->2

b. given linked list should behave like a stack . How?  eg. 1->2->3->4->5       print 5->4->3->2->1 [dont try to reverse it, it will take O(n)]

so print the linked list in reverse order at constant time.

time complexity O(1) ;

d. asked about the complexity of all sorting, best case as well as the worst case. Asked about Heap sort in detail and

Merge Sort.  if the complexity of both cases is O(nlong), So in which case you will use merge sort and Heap Sort.

How you will find nlogn —–> T(n).asked for mathematical calculation.

e.from tree he asked me to print the tree in spiral order. gfg it,

f.why we use Singleton class?

g. Question from java 8 (i told him m not confidence in that part.) so he moves on h. Abstract class and Interface.

Round 3: Technical Round 2

a. He asked me about some Architecture of Project (name m missing), But I told him I am working in Layered Architecture. So he started asking from that Architecture, How it works, and all functionality.

b.How two Application Communicate.

c. Framework M working.

d. He told me to design a database for e-commerce sites like Flipkart.

e.and Given me to write  SQL query, It was a bit complicated but I wrote the logic in java.

f.Question-related to Singleton class by emphasizing on my project.

this round did not go well.

Last word: You may leave for the day …….

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