2026 Blackrock Interview Questions

Quant Interview Questions

90 Questions

117

What are duration and convexity for bonds? Explain their definitions and how they are used in bond pricing and risk management.

Aladdin Client Service Analyst Interview

116

1. What is the difference between shallow copy and deep copy in C++? 2. Implement a class using the singleton pattern in Java. 3. Find the first common ancestor of two nodes in a binary search tree (BST).

Software Developer Intern Interview

115

Implement a hashMap data structure. What are the differences between a hashMap and a treeMap?

Software Engineer Intern Interview

112

In Java, how would you create a deck of cards and implement a method to shuffle them?

Software Engineer Interview

104

Find the least common ancestor of two nodes in an N-ary tree.

Software Engineer Interview

103

How do you convert an expression in infix (or prefix) notation to postfix notation?

Software Engineer Interview

102

Write a method that implements binary search.

Software Engineer Interview

101

Write a function that takes in a string and an integer n. The integer determines the maximum number of allowed repeated consecutive letters. For example, ('aab', 1) should return 'ab'. ('aaabba', 2) should return 'aabba'.

Software Engineer Interview

100

Implement a stack data structure that dynamically resizes its storage as elements are pushed and popped.

Software Engineer Interview

How does a HashMap find an entry, and what is the runtime of that search?

Software Engineer Interview

Why is multiple inheritance not supported in Java?

Software Engineer Interview

Given an array of integers (both positive and negative), find the maximum sum of any consecutive subarray.

Software Engineer Interview

Describe how a HashMap works.

Software Developer Interview

1. Reverse a string in place. 2. Write a method to convert a decimal number to binary. 3. What is the Singleton pattern? 4. What are the differences between Array and ArrayList in Java? 5. If you are going to design a phone directory, what data structure would you use? 6. Calculate Fibonacci numbers with and without recursion. For example, given an array [3, 5, 4], return the 3rd, 5th, and 4th Fibonacci numbers and store them in an array. What is the complexity of your algorithm? 7. Return the length of the last word in a sentence. For example: String s = 'Hello Wang' should return 4; String s2 = 'Hello ' should return 5; String s3 = '' should return 0. 8. Given an input number greater than 9, write a program that repeatedly sums all its digits until the sum is less than 10. For example, given 38: 3+8=11, 1+1=2, stop. 9. What are the differences between String, StringBuilder, and StringBuffer in Java?

Software Engineer Interview

How does a HashMap work internally?

Software Engineer Interview

Given a tree and two specified nodes, find their first common ancestor.

Software Engineer Interview

Sort a stack using only one other stack and a single variable.

Software Engineer Interview

What data structure would you use to build a parking lot, and why?

Software Engineer Interview

Implement an isEqual function to compare two objects and determine if they are equal.

Software Engineer Interview

Write the bubble sort algorithm.

Software Engineer Interview

What is the difference between an interface and an abstract class in Java? How does method overloading differ from method overriding? Can you explain the concept of encapsulation? What is the purpose of the 'final' keyword in Java?

Software Engineer Interview

Explain the keyword 'static' in the context of Java. What is its purpose and how is it used?

Software Developer Interview

Write a function that reverses a string.

Software Engineer Interview

Reverse the nodes of a linked list.

Software Engineer Interview

Arrange an array so that all zeros are on one side and all ones are on the other.

Software Engineer Interview

Write an algorithm that returns the Nth number in the Fibonacci sequence.

Software Engineer Interview

Write a function that returns the median of a list of numbers.

Software Engineer Interview

Given a binary search tree (BST) and a target value, find whether the element exists in the BST.

Software Developer Interview

What is object-oriented programming (OOP)? What is the difference between arrays and lists? How do you reverse an array?

Software Engineer Interview

1) Find the nth node from the end of a linked list. 2) Find the second largest number in an array.

Software Developer Interview

Given a singly linked list, find and return the middle node of the list. If there are two middle nodes, return the second middle node.

Software Developer Interview

Implement a solution to find the intersection node of two singly linked lists, starting from a brute-force approach to the most optimal solution. Also, implement the linked list data structure from scratch. Additionally, explain the differences between arrays and linked lists.

Software Engineer Interview

Answer the following programming questions: 1) Reverse a number. For example, input: 9966, output: 6699. 2) Count occurrences of each word in a string. For example, input: "The lovely lady is looking lovely as all lady look lovely", output: The: 1, lovely: 3, lady: 2, is: 1, looking: 1, as: 1, all: 1, look: 1. 3) Swap two numbers without using a temporary variable. For example, input: a = 10, b = 20; output: a = 20, b = 10.

Software Engineer Interview

Write an algorithm that sorts a hashmap.

Software Developer Interview

You have two strings and one lighter. How many minutes does it take for a string to disappear when you light both of its ends?

Analyst - Portfolio Analytics Group Interview

Explain the mathematical reasoning behind negative convexity.

PAG Analyst Interview

What are duration and convexity?

PAG Analyst Interview

Explain the concept of a left inner join.

Business Analyst Interview

Write a program to determine if the current configuration of a Tic Tac Toe board allows the 'X' player to win on their next move. A winning configuration is one where three 'X's appear in a row. Your task is to find if there is a row, column, or diagonal with exactly two 'X's and an empty spot, indicating that 'X' can win by playing in that spot. The program should output the coordinate (x, y) of the winning location.

Spring Week Interview

What is the duration of a bond? Explain how it is calculated.

PAG Analyst Interview

Given a binary search tree (BST) and two nodes, find their lowest common ancestor.

Business Analyst Interview

What are convexity and duration, and what is the difference between them?

Financial Analyst Interview

In the context of linear regression, what are the assumptions that should be checked before applying the model?

Financial Analyst Interview

Given a set of returns for a portfolio, calculate the variance of the portfolio.

Summer Internship Interview

You are given 8 identical-looking balls. Seven of the balls are equal in weight, and one of them is lighter. How would you efficiently find the lighter ball?

Software Engineer(Internship) Interview

How do you detect a cycle in a linked list?

Software Engineer(Internship) Interview

What is linear regression?

Summer Intern Interview

1. What are the differences between DDL, DML, and TCL in SQL? 2. How can you find the middle node of a singly linked list in a single pass? 3. How do you design a stack that can return the minimum element at any given time in constant time?

Internship Interview

How do you find the number of words in a file?

Internship Interview

Explain valuation techniques for pricing mortgage and corporate bonds.

Associate Interview

Design a cache system that stores key-value pairs with a fixed capacity. When the cache reaches its limit, it should evict the least recently used (LRU) entry. Implement methods to get a value by key, set a new key-value pair, and delete a specific key from the cache using a data structure of your choice.

Associate Interview

What is the Black-Scholes option pricing model?

Associate Interview

What is convexity? How is it calculated? What does it tell you?

Intern Interview

What is the angle between the hour hand and the minute hand of a clock at 3:15?

Intern Interview

1. Write an SQL query to find the second largest entry in a table. 2. Reverse the words in a sentence without using another string.

Intern Interview

How do you detect a cycle in a circular linked list?

Software Engineer Interview

In Java, how would you create a deck of cards and implement a method to shuffle them?

Software Engineer Interview

Find the least common ancestor of two given nodes in an N-ary tree.

Software Engineer Interview

How do you convert an expression in infix (prefix) notation to postfix notation?

Software Engineer Interview

Write a method to perform binary search on a sorted array.

Software Engineer Interview

Write a function that takes a string and an integer as inputs. The integer specifies the maximum number of consecutive repeated letters to allow in the returned string. For example: ('aab', 1) -> 'ab'; ('aaabba', 2) -> 'aabba'.

Software Engineer Interview

Implement a resizable stack data structure in your preferred programming language.

Software Engineer Interview

Given an array of integers (both positive and negative), find the maximum sum of consecutive integers.

Software Engineer Interview

Why is multiple inheritance not supported in Java?

Software Engineer Interview

How does a HashMap find an entry, and what is the runtime complexity of that search operation?

Software Engineer Interview

1. Reverse a string in place. 2. Write a method that converts a decimal number to binary. 3. What is a Singleton? 4. What are the differences between Array and ArrayList in Java? 5. If you were to design a phone directory, what data structure would you use? 6. Calculate Fibonacci numbers with and without recursion; for example, given an array [3, 5, 4], return the 3rd, 5th, and 4th Fibonacci numbers in an array. What is the complexity of your algorithm? 7. Return the length of the last word in a sentence. For example: String s = "Hello Wang" should return 4; String s2 = "Hello " should return 5; String s3 = "" should return 0. 8. Given a number greater than 9, write a program that repeatedly sums its digits until the result is less than 10 (e.g., 38 → 3+8=11, then 1+1=2, stop). 9. What are the differences between String, StringBuilder, and StringBuffer in Java?

Software Engineer Interview

Describe how a HashMap works.

Software Developer Interview

How does a HashMap work internally?

Software Engineer Interview

Find the first common ancestor of two given nodes in a tree.

Software Engineer Interview

Sort a stack using only one additional stack and a single variable.

Software Engineer Interview

What data structure would you use to build a parking lot, and why?

Software Engineer Interview

Implement an isEqual function to compare two objects and determine if they are equal.

Software Engineer Interview

Explain the use of the static keyword in the context of Java. What does it mean when a variable or method is declared static?

Software Developer Interview

What is the difference between an interface and an abstract class in Java? How does method overloading differ from method overriding? Can you explain the concept of encapsulation? What is the purpose of the 'final' keyword in Java?

Software Engineer Interview

Write the bubble sort algorithm.

Software Engineer Interview

Write a function that reverses a string.

Software Engineer Interview

Arrange an array so that all zeros are on one side and all ones are on the other side.

Software Engineer Interview

Reverse the nodes of a linked list.

Software Engineer Interview

Write a function that returns the median value from a given list of numbers.

Software Engineer Interview

Write an algorithm that returns the Nth number in the Fibonacci sequence.

Software Engineer Interview

Given a binary search tree (BST) and a target value, write an algorithm to determine if the value exists in the BST.

Software Developer Interview

1) Find the nth node from the end of a linked list. 2) Find the second largest number in an array.

Software Developer Interview

Given a singly linked list, find and return the value of the middle node.

Software Developer Interview

Solve the intersection of two linked lists from scratch, including implementing the linked list data structure. Start with a brute-force approach and optimize it. Also, explain the difference between arrays and linked lists.

Software Engineer Interview

1) Reverse a number: Given an integer input, output its digits in reverse order. For example, input: 9966, output: 6699. 2) Word count in a string: Given a string, return the count of each unique word. For example, input: 'The lovely lady is looking lovely as all lady look lovely' output: The: 1, lovely: 3, lady: 2, is: 1, looking: 1, as: 1, all: 1, look: 1. 3) Swap two numbers without using a temporary variable: Given two numbers, swap their values without using a third variable. For example, input: a = 10, b = 20. Output: a = 20, b = 10.

Software Engineer Interview

Given a string, determine if it is a palindrome, ignoring any characters that are not alphabetic.

Software Engineer Interview

Write an algorithm that sorts a hashmap.

Software Developer Interview

Describe Principal Component Analysis (PCA).

Summer Analyst Interview

Reverse a string in Java.

Summer Analyst Interview

What is the angle between the hour hand and the minute hand at 12:15 on a standard clock?

Summer Analyst Interview

If you have three rolls of a die, and after the first and second rolls you can choose either to accept your current roll or roll again, what is the optimal strategy to maximize your final roll, and what is the expected value of your outcome?

Summer Analyst Interview

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Blackrock

Interview Questions

Quant Interview Questions

How can you prevent gradient instability caused by the sigmoid function?

What are duration and convexity for bonds? Explain their definitions and how they are used in bond pricing and risk management.

1. What is the difference between shallow copy and deep copy in C++? 2. Implement a class using the singleton pattern in Java. 3. Find the first common ancestor of two nodes in a binary search tree (BST).

Implement a hashMap data structure. What are the differences between a hashMap and a treeMap?

What is the square of 72?

How can you join two database tables in SQL without using the JOIN keyword?

Write Python code to access specific data from Excel and CSV files.

Explain duration and its effect on bonds and bond valuations.

What are SQL correlated queries? Provide a definition and give an example.

How would you sort an array of numbers efficiently?

What are covariance and variance? Define each and explain their differences.

Derive the Ordinary Least Squares (OLS) estimator and discuss its bias.

How can you measure the extent to which the price of a security fluctuates?

In Java, how would you create a deck of cards and implement a method to shuffle them?

Find the least common ancestor of two nodes in an N-ary tree.

How do you convert an expression in infix (or prefix) notation to postfix notation?

Write a method that implements binary search.

Write a function that takes in a string and an integer n. The integer determines the maximum number of allowed repeated consecutive letters. For example, ('aab', 1) should return 'ab'. ('aaabba', 2) should return 'aabba'.

Implement a stack data structure that dynamically resizes its storage as elements are pushed and popped.

How does a HashMap find an entry, and what is the runtime of that search?

Why is multiple inheritance not supported in Java?

Given an array of integers (both positive and negative), find the maximum sum of any consecutive subarray.

Describe how a HashMap works.

How does a HashMap work internally?

Given a tree and two specified nodes, find their first common ancestor.

Sort a stack using only one other stack and a single variable.

What data structure would you use to build a parking lot, and why?

Implement an isEqual function to compare two objects and determine if they are equal.

Write the bubble sort algorithm.

What is the difference between an interface and an abstract class in Java? How does method overloading differ from method overriding? Can you explain the concept of encapsulation? What is the purpose of the 'final' keyword in Java?

Explain the keyword 'static' in the context of Java. What is its purpose and how is it used?

Write a function that reverses a string.

Reverse the nodes of a linked list.

Arrange an array so that all zeros are on one side and all ones are on the other.

Write an algorithm that returns the Nth number in the Fibonacci sequence.

Write a function that returns the median of a list of numbers.

Given a binary search tree (BST) and a target value, find whether the element exists in the BST.

What is object-oriented programming (OOP)? What is the difference between arrays and lists? How do you reverse an array?

1) Find the nth node from the end of a linked list. 2) Find the second largest number in an array.

Given a singly linked list, find and return the middle node of the list. If there are two middle nodes, return the second middle node.

Implement a solution to find the intersection node of two singly linked lists, starting from a brute-force approach to the most optimal solution. Also, implement the linked list data structure from scratch. Additionally, explain the differences between arrays and linked lists.

Write an algorithm that sorts a hashmap.

You have two strings and one lighter. How many minutes does it take for a string to disappear when you light both of its ends?

Explain the mathematical reasoning behind negative convexity.

What are duration and convexity?

Explain the concept of a left inner join.

What is the duration of a bond? Explain how it is calculated.

Given a binary search tree (BST) and two nodes, find their lowest common ancestor.

What are convexity and duration, and what is the difference between them?

In the context of linear regression, what are the assumptions that should be checked before applying the model?

Given a set of returns for a portfolio, calculate the variance of the portfolio.

You are given 8 identical-looking balls. Seven of the balls are equal in weight, and one of them is lighter. How would you efficiently find the lighter ball?

How do you detect a cycle in a linked list?

What is linear regression?

1. What are the differences between DDL, DML, and TCL in SQL? 2. How can you find the middle node of a singly linked list in a single pass? 3. How do you design a stack that can return the minimum element at any given time in constant time?

How do you find the number of words in a file?

Explain valuation techniques for pricing mortgage and corporate bonds.

What is the Black-Scholes option pricing model?

What is convexity? How is it calculated? What does it tell you?

What is the angle between the hour hand and the minute hand of a clock at 3:15?

1. Write an SQL query to find the second largest entry in a table. 2. Reverse the words in a sentence without using another string.

How do you detect a cycle in a circular linked list?

In Java, how would you create a deck of cards and implement a method to shuffle them?

Find the least common ancestor of two given nodes in an N-ary tree.

How do you convert an expression in infix (prefix) notation to postfix notation?

Write a method to perform binary search on a sorted array.

Write a function that takes a string and an integer as inputs. The integer specifies the maximum number of consecutive repeated letters to allow in the returned string. For example: ('aab', 1) -> 'ab'; ('aaabba', 2) -> 'aabba'.

Implement a resizable stack data structure in your preferred programming language.

Given an array of integers (both positive and negative), find the maximum sum of consecutive integers.

Why is multiple inheritance not supported in Java?

How does a HashMap find an entry, and what is the runtime complexity of that search operation?

Describe how a HashMap works.

How does a HashMap work internally?

Find the first common ancestor of two given nodes in a tree.

Sort a stack using only one additional stack and a single variable.

What data structure would you use to build a parking lot, and why?

Implement an isEqual function to compare two objects and determine if they are equal.