Blackrock interview experience Real time questions & tips from candidates to crack your interview
SDE - 1
Blackrock
3 rounds | 3 Coding
problems
Selected Interview preparation journey
Preparation
Duration: 6 months
Topics: DSA, oops, OS, DBMS, CN, low level design
Tip 1 : Tree is the most important topic in BlackRock recruitment process.
Tip 2 : have atleast one live working project- host your project either on Heroku/Play Store.
Tip 3 : Practice atleast 100 leetcode medium questions.
Application process
Where: Campus
Eligibility: Above 6CGPA, no backlog
Tip 1 : Don't oversell yourself because interviewers will grind you on everything that you write in resume.
Tip 2 : Mention links to your project.
Interview rounds
01
Round
Medium
Online Coding Interview
Duration90 minutes
Interview date22 Aug 2021
Coding problem0
Online Assessment consisted of 3 sections:
1. Aptitude : This section consisted of several sub-sections like Logical Reasoning, Attention to Detail, etc. with different time limits for each of the sub-sections. My advice to crack this round will be not to stick and waste time on a single question but instead, try to solve maximum questions.
2. Programming Ability: This section had algorithm design questions that were in the form of a flow chart with different steps to complete the algorithm stated in them and some blank spaces in between to be filled by us. Basic knowledge in algorithm design and a little reasoning can help solve these kinds of questions. This round had MCQ questions that focused mostly on TREE data structure with multiple questions on traversals and AVL TREE insertions and deletions. My advice will be to study the TREE data structure properly to gain some advantage in this section.
3. SQL: This section entirely focused on questions related to SQL queries, syntaxes, aggregate functions, and DBMS concepts, write small queries etc. My advice will be to have enough practice on SQL from websites like Leetcode and Hackerrank.
02
Round
Hard
Video Call
Duration100 Minutes
Interview date24 Aug 2021
Coding problem3
There were 2 interviewers. It started with an introduction from me and one of the interviewers directly started with a DSA questions. Two problems were asked and I had to code them on a compiler of my choice by sharing my screen. Level of DSA question was medium but I was severely grilled on oops. I had to create different abstract classes, interface and explain entire oops with examples.
This was followed by a set of core JAVA questions :
Difference between == and .equals() ?
Mention some methods of the object class?
Difference between TreeSet and SortedSet?
How is a String saved in JAVA?
difference between string pool and heap memory?
1. Shortest Distance
Easy
10m average time
90% success
0/40
Asked in companies
You have been given a Binary Search Tree and two keys 'NODE1' and 'Node2' in it.
Your task is to find the shortest distance between two nodes with the given two keys. It may be assumed that both keys exist in BST.
Example:
For the above BST:
‘NODE1’ = 6, ‘NODE2’ = 14
Distance between 6 and 14 = (Number of nodes in the path from 6 to 14) + 1.
So the path from 6 to 14 is : ( 6 -> 3 -> 8 -> 10 -> 14).
Distance between 6 and 14 = 3 ( i.e. 3, 8, 10 are in path) + 1 = 4.
Problem approach
I directly gave an approach to find the lowest common ancestor of the two nodes and then finding separate distances between the Ancestor node and the two nodes and returning the sum of the distances. I was then asked to code the whole solution which I correctly completed.
2. Greatest Common Divisor
Easy
15m average time
85% success
0/40
Asked in companies
You are given two numbers, ‘X’ and ‘Y’. Your task is to find the greatest common divisor of the given two numbers.
The Greatest Common Divisor of any two integers is the largest number that divides both integers.
For Example:
You are given ‘X’ as 20 and ‘Y’ as 15. The greatest common divisor, which divides both 15 and 20, is 5. Hence the answer is 5.
Problem approach
I was happy after seeing the question and coded it in 3 minutes using while loop. I was the asked to do it by recursion and i successfully did it but the catch here was to explain to the interviewer the entire memory management in heap and stack along with complexity solution.
3. Bridges In A Graph
Moderate
25m average time
65% success
0/80
Asked in companies
Given an undirected graph of V vertices and E edges. Your task is to find all the bridges in the given undirected graph. A bridge in any graph is defined as an edge which, when removed, makes the graph disconnected (or more precisely, increases the number of connected components in the graph).
For Example :
If the given graph is :
Then the edge between 0 and 4 is the bridge because if the edge between 0 and 4 is removed, then there will be no path left to reach from 0 to 4.and makes the graph disconnected, and increases the number of connected components.
Note :
There are no self-loops(an edge connecting the vertex to itself) in the given graph.
There are no parallel edges i.e no two vertices are directly connected by more than 1 edge.
Problem approach
I solved it using o(e+v) algo and interviewers were very patient and helpful
04
Round
Easy
Video Call
Duration30 Minutes
Interview date25 Jan 2022
Coding problem0
It was a general HR round where i was asked about my projects and certain other aspects like relocation, hobbies. Since my area of interest was AI, we had a wholesome discussion on future of AI. Then she asked me some general questions about my hobbies, tech stack, and language I am comfortable in, availability for relocation, and previous internship experience.
Then she asked if I had any questions and I happily asked about life at Blackrock and her experience as a Blackrock employee.
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Skill covered: Programming
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