BlackRock interview questions
Online test → Technical → HR
CS fundamentals
Showing 33 of 91 reported in this area
Find the output of SQL queries.
What is a smart pointer in C++?
Explain the volatile keyword in Java
How does the garbage collector work?
Explain RAID and its different levels.
How is a String stored in Java memory?
Explain the String Pool concept in Java
Explain how vector works internally in C++.
How can errors be reduced in linear regression?
Write a program that creates a dangling pointer
Explain JWT tokens and their use in authentication.
How do you implement a const member function in C++?
SQL query using joins and subqueries on three tables
Difference between String pool and heap memory in Java
Write code to demonstrate runtime polymorphism in C++.
Explain the four pillars of object-oriented programming.
Explain AWS Lambda and its use cases in a backend system.
Explain compile-time polymorphism and runtime polymorphism.
Explain synchronization in Java and how threads are managed
How does a Django backend connect to a PostgreSQL database?
Write an SQL query using JOINs and a query using a subquery.
Explain const and static keywords in C++ and their differences.
How do you find a particular word from a given sentence using R?
Write an SQL query to find the second-highest record from a table.
How is data stored and formatted in MongoDB, and when should it be used?
What are AWS IAM roles and how are they configured and used in applications?
Choose the correct SQL query to produce the given output from a provided database schema.
Find the output of C programs and data structure code involving trees and tree traversals.
Explain the difference between compareTo(), equals(), and == when comparing strings in Java.
Is it possible to change the data of a variable inside a const member function? If yes, how?
Explain OOP concepts in C++ such as inheritance, operator overloading, and method overriding.
What is a deadlock in operating systems and what are the necessary conditions for it to occur?
Write SQL queries to find the highest, second-highest, and fourth-highest salary from a table.
DSA
Showing 17 of 48 reported in this area
Perform inorder, preorder, and postorder traversals of a given binary tree.
Explain a shortest path algorithm used in graphs.
Write code to find the Right View of a Binary Tree.
Find the next greater number with the same set of digits
Explain merge sort and quick sort algorithms and compare them.
Answer questions on tree traversals and properties of AVL trees.
Given an array of integers, find all possible Pythagorean triplets.
Find the shortest distance between two nodes in a Binary Search Tree
Find the length of the longest substring without repeating characters
Compare all major sorting algorithms based on time and space complexity.
Explain AVL trees and answer questions related to balancing and rotations.
Find all distinct pairs in an array whose sum is equal to a given number K.
Form a Binary Search Tree and determine its preorder and postorder traversals.
Implement a Stack using Queues and explain the approach with sample input/output
Count ASCII values of characters in a string and replace them with the maximum value.
Find all pairs in an array such that their sum is equal to K without using a hashmap.
Optimize the code for generating the Fibonacci series and explain the approach from scratch.
Aptitude
Showing 4 of 18 reported in this area
Solve logical reasoning questions based on patterns and deductions.
Answer attention-to-detail questions accurately under strict time limits.
Solve aptitude problems involving quantitative reasoning under time constraints.
Logical reasoning and mathematical aptitude questions (including attention to detail)
Puzzles
Showing 3 of 6 reported in this area
Using 6 matchsticks, how can you form 4 triangles?
Given two hourglasses of 4 minutes and 7 minutes, measure exactly 9 minutes
A test lasts 15 minutes. Using one 7-minute and one 11-minute hourglass, and turning them only 3 times in total, how can you measure exactly 15 minutes?
Behavioural
2 questions reported in this area
Describe a failure you have faced and explain how you dealt with it.
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Describe an incident where you faced obstacles or challenges and how you overcame them.
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System design
Showing 1 of 2 reported in this area
How would you scale an application when moving from a 2-tier architecture to a 3-tier architecture?
Showing 60 of 145 questions. Ranked by how often the same question came back across reports.
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What questions does BlackRock ask?
Candidate interview reports most often cover CS fundamentals (54%) and DSA (29%).
How many rounds does BlackRock interview have?
Candidate interview reports show an average of 3.1 rounds per experience, with a typical sequence of Online test → Technical → HR. Individual interview paths can vary.
Is the BlackRock interview hard?
Among questions with a reported difficulty, the mix is easy 48%, medium 49%, hard 3%.