30+ Morgan Stanley Software Developer Interview Questions and Answers

Sort a list of event dates in ascending order based on year, month, and day.

• Sort the list of dates based on year, then month, and finally day.

• Use a sorting algorithm to rearrange the dates in ascending order.

• Ensure the constraints are met for each date in the list.

Count the number of distinct elements in every K-sized window of an array.

• Use a sliding window approach to keep track of distinct elements in each window

• Use a hashmap to store the frequency of elements in the current window

• Update the hashmap as you slide the window to the right and maintain the count of distinct elements

• Return the count of distinct elements for each window

Find the shortest path between two nodes in a tree.

• Use BFS to traverse the tree and find the shortest path between the two nodes.

• Maintain a parent array to backtrack from the target node to the source node.

• Output the path by backtracking from the target node to the source node using the parent array.

Given an array and a target sum, find all pairs of elements that add up to the target sum.

• Iterate through the array and for each element, check if the complement (target sum - current element) exists in a hash set.

• If the complement exists, add the pair to the result list.

• Sort the pairs based on the first element and then the second element.

• Handle edge cases like duplicate elements and pairs with the same values.

• Example: For input N=5, S=7, ARR=[3, 1, 2, 4, 5], the output shou...read more

Given an integer N, recursively break it into three parts and find the maximum sum possible.

• Recursively divide N into N/2, N/3, and N/4 to find the maximum sum

• Compare the sum obtained by dividing N with the sum of N itself

• Return the maximum sum for each test case

Calculate minimum weight capacity needed to deliver all packages within 'D' days.

• Iterate through the array of weights to find the maximum weight

• Use binary search to find the minimum weight capacity needed

• Check if the total weight loaded each day does not exceed the ship's maximum weight capacity

Find the highest value that occurs the same number of times within an array.

• Iterate through the array and count the occurrences of each value.

• Store the counts in a dictionary or hash map.

• Find the maximum count and check which value(s) have that count.

• Return the highest value among those with the maximum count.

Bubble Sort is used to sort an array of non-negative integers in non-decreasing order by swapping adjacent elements if they are not in the correct order.

• Iterate through the array and compare adjacent elements, swapping them if they are in the wrong order.

• Repeat this process until the array is sorted in non-decreasing order.

• Time complexity of Bubble Sort is O(n^2) in worst case.

• Example: For input [6, 2, 8, 4, 10], the output should be [2, 4, 6, 8, 10].

Determine the minimum number of candies needed to distribute to students based on their performance and ratings.

• Iterate through the array of student ratings and assign 1 candy to each student initially.

• Then iterate from left to right and check if the current student's rating is higher than the previous student, if so, assign candies accordingly.

• Similarly, iterate from right to left to handle cases where the current student's rating is higher than the next student.

• Keep track o...read more

Implement a function to perform topological sorting on a directed acyclic graph (DAG) and return any valid ordering.

• Create a graph data structure to represent the DAG

• Use depth-first search (DFS) to perform topological sorting

• Maintain a visited array to keep track of visited nodes

• Return the ordering of nodes after DFS traversal

Find the duplicate number in an integer array containing numbers from 0 to (N - 2).

• Iterate through the array and keep track of the frequency of each number using a hashmap.

• Return the number that appears twice in the array.

• The duplicate number is always present in the given array.

Find the shortest path between two houses in a city represented as an unweighted graph.

• Use breadth-first search (BFS) algorithm to find the shortest path in an unweighted graph.

• Start BFS from the source house and keep track of the shortest path to each house.

• Once the destination house is reached, backtrack to find the shortest path.

• Consider using a queue data structure to implement BFS efficiently.

Calculate the total amount of rainwater that can be trapped within given elevation map.

• Iterate through the array to find the maximum height on the left and right of each bar.

• Calculate the amount of water that can be trapped above each bar by taking the minimum of the maximum heights on the left and right.

• Sum up the trapped water above each bar to get the total trapped water for the elevation map.

Given a BST and a target value, find if there exists a pair of node values in the BST whose sum equals the target value.

• Traverse the BST in-order and store the node values in a set while checking for the target value difference.

• Use two pointers approach to find the pair of values that sum up to the target value.

• Consider edge cases like negative values and handling duplicates in the BST.

Identify the duplicate integer in an array containing numbers between 1 and N-1.

• Iterate through the array and keep track of the frequency of each element using a hashmap.

• Return the element with a frequency greater than 1 as the duplicate integer.

• Ensure the constraints are met and a duplicate number is guaranteed to be present.

Logic to get Map using Stream API to show balance of each person

• Use Stream API to group accounts by name

• Use map() to get the sum of balances for each group

• Collect the results into a Map

Calculate the total sum of all root to leaf paths in a binary tree formed by concatenating node values.

• Traverse the binary tree from root to leaf nodes, keeping track of the current path sum

• Add the current node value to the path sum and multiply by 10 for each level

• When reaching a leaf node, add the final path sum to the total sum

• Return the total sum modulo (10^9 + 7)

Find the Lowest Common Ancestor (LCA) of two nodes in a binary tree.

• Traverse the binary tree to find the paths from the root to nodes X and Y.

• Compare the paths to find the last common node, which is the LCA.

• Handle cases where one node is an ancestor of the other.

• Consider edge cases like when X or Y is the root node.

• Implement a recursive or iterative solution to find the LCA efficiently.

Implement a function to find the minimum number in a rotated sorted array efficiently.

• Use binary search to find the minimum element in the rotated array.

• Compare the mid element with the start and end elements to determine which half of the array to search next.

• Continue the binary search until the minimum element is found.

Construct a maximum binary tree from an array of unique integers following specific rules.

• Find the maximum number in the array to set as the root of the tree.

• Recursively construct the left subtree with elements before the maximum number.

• Recursively construct the right subtree with elements after the maximum number.

Weak reference is a reference that does not prevent the object from being garbage collected.

• Weak references are used to refer to objects that can be garbage collected if there are no strong references to them.

• They are typically used in scenarios where you want to hold a reference to an object, but don't want to prevent it from being collected.

• Weak references are implemented using weak reference queues, which allow you to perform actions when weakly referenced objects are abou...read more

Count occurrences of a character in a string and output in a specific format.

• Use a hash table to store the count of each character.

• Loop through the string and update the count in the hash table.

• Create the output string using the hash table.

HashSet is implemented using a HashMap internally. Same hashcode is generated when two objects have the same value for hashCode() and equals() methods.

• HashSet internally uses a HashMap to store its elements.

• The hashcode of an object is generated using the hashCode() method.

• If two objects have the same value for hashCode() and equals() methods, they will generate the same hashcode.

• For example, if two String objects have the same content, they will generate the same hashcode.

Singleton pattern ensures a class has only one instance, while allowing global access to it.

• Implement a private constructor to prevent direct instantiation.

• Create a static method to provide a single point of access to the instance.

• Use lazy initialization to create the instance only when needed.

• Ensure thread safety in a multithreaded environment using synchronization or double-checked locking.

• Breaking the singleton pattern can be done by using reflection, serialization, or clo...read more

SQL Cursor is a database object used to manipulate data row by row.

• Cursor is used to fetch and process data row by row

• Index is a database object used to speed up data retrieval

• Aggregate functions are used to perform calculations on a set of values

• Examples of aggregate functions are SUM, AVG, COUNT, MAX, MIN

I want to work at Morgan Stanley because of its reputation for excellence in finance, global presence, and opportunities for growth.

• Morgan Stanley is a renowned financial institution known for its excellence in finance

• I am attracted to the global presence of Morgan Stanley and the opportunity to work on international projects

• I believe working at Morgan Stanley will provide me with opportunities for professional growth and development

Annotations used in Spring Framework for defining components and services.

• Annotations like @Component, @Service, and @Controller are used for defining components in Spring Framework.

• @RestController is used for defining RESTful web services.

• @Configuration is used for defining configuration classes.

• @Transactional is used for defining transactional methods.

• All these annotations help in defining and managing dependencies in Spring Framework.

Converts a string from Camel case to Snake case.

• Loop through the string and check for uppercase letters

• Insert an underscore before each uppercase letter

• Convert the string to lowercase

Optimized solutions and core principles applied in OOPS

• Encapsulation, Inheritance, Polymorphism, Abstraction are core principles of OOPS

• Optimized solutions can be achieved through efficient algorithms and data structures

• Design patterns like Singleton, Factory, Observer can also be used for optimized solutions

To check palindrome and anagram of a string with O(n), use a hash table to store character frequencies.

• Create a hash table to store the frequency of each character in the string.

• For palindrome, check that no more than one character has an odd frequency.

• For anagram, compare the hash tables of the two strings.

• If the hash tables are equal, the strings are anagrams.

• If the hash tables differ by only one character, the strings are palindrome anagrams.

• If the hash tables differ by mo...read more

Coin change problem can be solved using dynamic programming to find the minimum number of coins needed to make a certain amount of change.

• Use dynamic programming to build up solutions for smaller subproblems

• Start by initializing an array to store the minimum number of coins needed for each amount from 0 to the target amount

• Iterate through each coin denomination and update the array with the minimum number of coins needed for each amount

Find the Kth maximum element in an array of strings.

• Sort the array in descending order.

• Return the element at index K-1.