Microsoft Corporation Software Developer Interview Questions, Process, and Tips

Round duration - 90 minutes
Round difficulty - Easy

Pretty easy questions.

Q1. 
Kth Smallest Element Problem Statement
You are provided with an array of integers ARR of size N and an integer K. Your task is to find and return the K-th smallest value present in the array. All elements...read more
Ans. 
Find the K-th smallest element in an array of distinct integers.
• Sort the array and return the element at index K-1.

• Use a min-heap to find the K-th smallest element efficiently.

• Implement quickselect algorithm for optimal performance.
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Round duration - 20 Minutes
Round difficulty - Easy

1 coding question

Q1. 
IP Address Formation from String
Given a string S consisting only of digits from 0 to 9, your task is to find all potential IP addresses that can be formed from S and list them in lexicographical order. I...read more
Ans. 
Given a string of digits, find all potential valid IP addresses that can be formed from it.
• Split the string into four parts and check if each part is a valid IP segment (0-255).

• Use backtracking to generate all possible combinations of valid IP addresses.

• Ensure that the IP address does not contain leading zeroes.

• Return the valid IP addresses in lexicographical order.
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Round duration - 45 Minutes
Round difficulty - Easy

Total Discussion on OS concepts

Q1. Can you explain the concepts related to memory management in operating systems?
Ans. 
Memory management in operating systems involves allocation, deallocation, and optimization of memory usage.
• Memory allocation: OS allocates memory to processes based on their requirements.

• Memory deallocation: OS frees up memory when it is no longer needed by a process.

• Memory optimization: OS optimizes memory usage through techniques like paging, segmentation, and virtual memory.

• Examples: Paging in which memory is divide...read more
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Round duration - 45 Minutes
Round difficulty - Easy

Easy in office environment

Q1. 
Find the Lone Set Bit
Your task is to identify the position of the only '1' bit in the binary representation of a given non-negative integer N. The representation contains exactly one '1' and the rest are...read more
Ans. 
Find the position of the lone '1' bit in the binary representation of a given non-negative integer.
• Iterate through the bits of the integer to find the position of the lone '1'.

• Use bitwise operations to check if there is exactly one '1' bit in the binary representation.

• Return the position of the lone '1' or -1 if there isn't exactly one '1'.
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Round duration - 60 Minutes
Round difficulty - Easy

Q1. 
Spiral Order Traversal of a Binary Tree Problem Statement
Given a binary tree with 'N' nodes, your task is to print the nodes in spiral order traversal.
Example:
Input:
The binary tree is represented i...read more
Ans. 
Print nodes of a binary tree in spiral order traversal.
• Use a queue to perform level order traversal of the binary tree.

• Alternate between printing nodes from left to right and right to left at each level.

• Handle null nodes represented by '-1' appropriately.

• Example: For input '1 2 3 -1 -1 4 5 -1 -1 -1 -1', the output should be '1 3 2 4 5'.
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Round duration - 60 Minutes
Round difficulty - Easy

Q1. 
Word Break Problem Statement
You are given a list of N strings called A. Your task is to determine whether you can form a given target string by combining one or more strings from A.
The strings from A c...read more
Ans. 
Given a list of strings, determine if a target string can be formed by combining one or more strings from the list.
• Iterate through all possible combinations of strings from the list to form the target string.

• Use recursion to try different combinations of strings.

• Check if the current combination forms the target string.

• Return true if a valid combination is found, otherwise return false.
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Round duration - 60 Minutes
Round difficulty - Easy

Q1. Design an elevator system.
Ans. 
Design an elevator system for efficient vertical transportation.
• Divide building into zones to optimize elevator usage.

• Implement algorithms for efficient elevator scheduling.

• Include safety features like emergency stop buttons and overload sensors.

• Consider user interface for passengers to select floors and monitor elevator status.
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Round duration - 90 minutes
Round difficulty - Hard

Online coding contest, focus on DP and trees

Q1. 
Chess Tournament Problem Statement
In Ninjaland, a chess tournament is being organized with C chess players attending. They will all stay in a hotel that has N available rooms. Each player will choose one...read more
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Round duration - 45 minutes
Round difficulty - Hard

It was conducted on the GHCI conference itself. It was held in a Microsoft interview room at the career fair of the conference. This was primarily based on my coding abilities and understanding how to optimise a solution

Q1. 
Check Word Presence in String
Given a string S and a list wordList containing N distinct words, determine if each word in wordList is present in S. Return a boolean array where the value at index 'i' indi...read more
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Round duration - 30 minutes
Round difficulty - Medium

This was a system design round.

Round duration - 20 minutes
Round difficulty - Easy

This was the HR round and only typical HR questions were asked.

Round duration - 45 minutes
Round difficulty - Medium

It was an online round hosted on cocubes. It consisted of 3 coding questions only and the duration of the test was 45 mins. 
The test link with a unique id and password was sent to the email 1 day prior to the test day. It consisted to platform specification, sample test etc.

On the day of test, we were given a time slot of 5pm - 11pm. We could attempt the test as per our comfort.
The instructions were pretty straightforward and we could attempt it from anywhere. 

There were only 2 requirements. A webcam must be available. And a decent internet. 

About the Platform. 
In all of the problems base classes and code were disabled, we needed to implement only certain classes/ functions. Clipboard copy was blocked, tab switching was not allowed and rest the platform is very basic and simple.

Q1. 
Add Two Numbers Represented by Linked Lists
Given two singly linked lists, each representing a positive number without leading zeros, your task is to add these two numbers. The result should be returned a...read more
Ans. 
Add two numbers represented by linked lists and return the sum as a linked list.
• Traverse both linked lists simultaneously while keeping track of carry.

• Create a new linked list to store the sum.

• Handle cases where one linked list is longer than the other.

• Update the next pointer of the current node to point to the new node with the sum.

• Handle the carry if it exists after reaching the end of both linked lists.
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Q2. 
Maximum Subarray Sum Problem Statement
Given an array 'ARR' of integers with length 'N', the task is to determine the sum of the subarray (including an empty subarray) that yields the maximum sum among al...read more
Ans. 
Find the maximum sum of a subarray in an array of integers.
• Iterate through the array and keep track of the maximum sum subarray ending at each index.

• Use Kadane's algorithm to efficiently find the maximum subarray sum.

• Consider the case where all elements are negative, in which case the maximum sum would be the largest negative number.
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Q3. 
Sum of Leaf Nodes at Maximum Level Problem Statement
Given a binary tree of integers, your task is to calculate the sum of all the leaf nodes which are present at the deepest level of the binary tree. If ...read more
Ans. 
Calculate the sum of leaf nodes at the deepest level of a binary tree.
• Traverse the binary tree to find the deepest level.

• Keep track of leaf nodes at the deepest level and calculate their sum.

• Handle null nodes represented by -1.

• Ensure the sum fits in a 32-bit integer.
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Round duration - 60 minutes
Round difficulty - Hard

This round is known as the group fly round. After clearing the first round, we were called at the Microsoft Gurgaon office for the face to face interviews. Approximately, 60 students were there on the day I was called. I guess there were multiple days for multiple slots.

We all were divided into groups of 6-8 people and were called inside a round table room with 1 interviewer. This round consisted of 1 problem only to be discussed over with the interviewer. And the solutions to be written on pen paper. 

The key here is to walk through the thought process and the steps with the interviewer. He will go around the table and will have discussion with each one of us and discuss about the pros, cons of the solutions.

It is advisable to ask as many questions as possible, to gather requirements and to be sure what are the expectations.
 

Round duration - 60 minutes
Round difficulty - Medium

This was the first face to face round. 
It was held just after the group fly. From my group fly slot, 2/7 were selected. 
The interviewer made me comfortable, we started informal talks about college and hobbies. 

It kicked off with some basic discussion of the previous round problems, he had some questions about the encryption and security related stuff from payment scenario. 

Then there were some behavioral questions and lastly there were a couple of whitepaper coding questions.

Q1. 
N-Queens Problem Statement
Given an integer N, your task is to position N queens on an N x N chessboard in such a way that no two queens threaten each other.
A queen can attack other queens that are in t...read more
Ans. 
Position N queens on an N x N chessboard so that no two queens threaten each other.
• Use backtracking to explore all possible configurations.

• Keep track of rows, columns, and diagonals to ensure no two queens threaten each other.

• Display all valid configurations found.
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Q2. 
Left View of a Binary Tree Problem Statement
Given a binary tree, your task is to print the left view of the tree.
Example:
Input:
The input will be in level order form, with node values separated by a...read more
Ans. 
Print the left view of a binary tree given in level order form.
• Traverse the tree level by level and print the first node of each level (leftmost node).

• Use a queue to keep track of nodes at each level.

• Time complexity should be O(n) where n is the number of nodes in the tree.
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Round duration - 45 minutes
Round difficulty - Easy

This was the second face to face. Almost 50% students were selected from the first face to face round. 
This was very straightforward round, a hectic day and it was already late by now. 
The interviewer started with formal introduction and gave me 2 very basic problems to code. 

This code consists of writing the entire code from scratch on whitepaper, with unit tests that can cover almost all scenarios. Some sample test cases were given by the interviewer at the end, to validate and dry run my solution.

Q1. 
Cycle Detection in a Linked List
Determine if a given Singly Linked List of integers forms a cycle or not.
Explanation:
A cycle occurs when a node's next points back to a previous node in the list. This...read more
Ans. 
Detect if a singly linked list forms a cycle by checking if a node's next pointer points back to a previous node.
• Traverse the linked list using two pointers, one moving one step at a time and the other moving two steps at a time.

• If the two pointers meet at any point, there is a cycle in the linked list.

• If one of the pointers reaches the end of the list (null), there is no cycle.
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Q2. 
Maximum Path Sum Between Two Leaves of a Binary Tree Problem Statement
You are provided with a non-empty binary tree where each node has a non-negative integer value. Compute and return the maximum possib...read more
Ans. 
Find the maximum path sum between two leaves in a binary tree.
• Traverse the binary tree to find the maximum path sum between two leaves.

• Keep track of the maximum sum encountered during traversal.

• Consider all possible paths that include leaf nodes.

• Handle cases where there is only one leaf node or no leaf nodes.

• Implement a recursive function to calculate the maximum path sum.
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Round duration - 30 minutes
Round difficulty - Easy

This was the final round. 
It was very late in the evening, around 10pm. 
The interviewer here was one of the senior manager in the org (M2). 

This kicked off with very informal conversations and introductions. 
The interviewer was very engaging.