30+ Mts1 Interview Questions and Answers

Check if two expressions are equivalent by evaluating them with different variable assignments.

• Parse the expressions to evaluate them with different variable assignments.

• Use a stack to keep track of operands and operators while evaluating the expressions.

• Compare the results of both expressions to determine if they are equivalent.

Determine the minimum number of platforms needed at a railway station so that no train has to wait.

• Sort the arrival and departure times arrays in ascending order.

• Initialize two pointers for arrival and departure times, and a variable to keep track of the maximum number of platforms needed.

• Increment the platform count when a train arrives and decrement when a train departs.

• Update the maximum platform count as needed.

• Return the maximum platform count at the end.

Identify numbers whose sum with digits equals given integer N.

• Iterate through numbers from 1 to N and check if sum of number and its digits equals N.

• Use a helper function to calculate sum of digits for a given number.

• Return -1 if no such number exists for a test case.

Find and return the value of (i * i + j * j) for elements in a 2D array where the sum of the cubes of its digits equals the element itself.

• Iterate through the 2D array and check if the sum of the cubes of the digits equals the element itself.

• Calculate (i * i + j * j) for elements that satisfy the condition.

• Return the calculated values as output.

• If no element satisfies the condition, return -1.

Detect if a singly linked list forms a cycle by checking if a node's next 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, it indicates the presence of a cycle in the linked list.

• To optimize, use Floyd's cycle detection algorithm for O(N) time complexity and O(1) space complexity.

The task is to maximize the sum of selected elements from an array by following specific rules.

• Select elements strategically to maximize the sum

• Remove occurrences of selected element, and its neighbors

• Repeat the process until the array becomes empty

Given a preorder traversal of a BST, construct the BST and print its inorder traversal.

• Parse the input to get the number of test cases and preorder traversal for each case

• Construct the BST using the preorder traversal by recursively building the tree

• Print the inorder traversal of the constructed BST for each test case

Determine the maximum amount of money a thief can steal from houses without looting two consecutive houses.

• Create an array 'dp' to store the maximum money that can be stolen up to the i-th house.

• Iterate through the houses and update 'dp' based on whether the current house is stolen or not.

• Return the maximum value in 'dp' as the answer.

Implement a function to find the maximum possible height of a stack of boxes given their dimensions.

• Create all possible rotations of each box to consider all orientations for stacking

• Sort the boxes based on their base dimensions in non-increasing order

• Use dynamic programming to find the maximum height of the stack

The task is to find the minimum number of operations required to create a valid path from node A to node B by reversing edges in a directed graph.

• Iterate through the graph to find the shortest path from node A to node B.

• Use a graph traversal algorithm like BFS or DFS to explore possible paths.

• Track the number of edge reversals needed to reach node B from node A.

• Consider edge directions and reverse them as needed to create a valid path.

• Return the minimum number of edge reversa...read more

The task is to rearrange an array such that no two adjacent elements are the same.

• Iterate through the array and check if any adjacent elements are the same.

• If adjacent elements are the same, swap one of them with a different element.

• Return 'YES' if a valid rearrangement is possible, 'NO' otherwise.

The task is to find the length of the longest increasing path in a matrix starting from a given cell.

• Create a recursive function to explore all possible paths from the starting cell, keeping track of the length of each path.

• Use dynamic programming to avoid redundant calculations and optimize the solution.

• At each cell, check if moving to the right or down is possible and leads to an increasing path.

• Update the length of the longest increasing path found so far as you explore di...read more

Implement a function to process queries on a binary matrix by flipping elements and counting zeros in rows/columns.

• Create a binary matrix with all elements initialized to 0.

• Process queries of type 1 by flipping elements in the specified row/column.

• Process queries of type 2 by counting the number of zeros in the specified row/column.

• Return the count of zeros for type 2 queries.

• Ensure to handle the constraints provided in the problem statement.

Check if a given string represents a valid binary number composed of 0s and 1s.

• Iterate through each character in the string and check if it is either '0' or '1'.

• If any character is not '0' or '1', return 'false'.

• Return 'true' if all characters are '0' or '1'.

The problem involves determining the lexicographic permutation rank of a distinct string.

• Iterate through all permutations of the string and compare with the given string to determine the rank.

• Use a recursive function to generate all permutations of the string.

• Keep track of the count of permutations smaller than the given string to determine the rank.

Convert a binary tree into its mirror tree by interchanging left and right children of non-leaf nodes.

• Traverse the tree in a recursive manner and swap the left and right children of each node.

• Modify the binary tree in place to get the mirror, without creating a new tree.

• Use a temporary variable to swap the left and right children of each node.

Level Order Traversal of Binary Tree returns nodes in level order traversal.

• Perform a level order traversal of the binary tree starting from the root node.

• Visit nodes level by level, printing them in the order they are encountered.

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

The task is to print the Top View of a Binary Tree, which is the set of nodes visible when viewed from the top, in left to right order.

• Traverse the binary tree in level order and maintain a map to store the horizontal distance of each node from the root.

• For each node, if the horizontal distance is not already in the map, add the node's value to the result.

• Print the values from the map in ascending order of horizontal distance to get the Top View of the Binary Tree.

Calculate the number of distinct ways to climb N stairs by either taking one or two steps at a time.

• Use dynamic programming to keep track of the number of ways to reach each stair

• The number of ways to reach a stair is the sum of the number of ways to reach the previous two stairs

• Return the result modulo 10^9+7

Yes, we can solve this problem using a time complexity of O(max(N, M)) by using a two-pointer approach.

• Use two pointers to iterate through both arrays simultaneously.

• Compare the elements at the pointers and move the pointers accordingly to find the intersection.

• This approach ensures linear time complexity based on the size of the larger array.

Designed a scalable system for Pastebin with various requirements.

• Implemented a distributed system architecture to handle high traffic and ensure reliability.

• Used load balancing techniques to evenly distribute incoming requests across multiple servers.

• Implemented data sharding to partition data across multiple databases for efficient storage and retrieval.

• Utilized caching mechanisms to improve performance and reduce latency.

• Implemented access control mechanisms to ensure data...read more

Reverse a given string containing characters from [a-z], [A-Z], [0-9], and special characters.

• Iterate through each character in the string and append them in reverse order to a new string

• Use built-in functions like reverse() or slice() to reverse the string

• Handle special characters and numbers along with alphabets

Implement in-order traversal of a binary tree without recursion.

• Use a stack to simulate the recursive in-order traversal process.

• Start with the root node and keep traversing left until reaching a null node, pushing nodes onto the stack.

• Pop nodes from the stack, print the value, and move to the right child if it exists.

• Continue this process until the stack is empty and all nodes have been visited.

The task is to 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.

• Consider null nodes as well while traversing the tree.

The result of adding two binary numbers in a 64-bit and a 32-bit operating system will differ due to the different number of bits used for calculations.

• In a 64-bit operating system, the result will be more accurate and can handle larger numbers compared to a 32-bit system.

• Overflow may occur in a 32-bit system when adding large binary numbers, leading to incorrect results.

• Example: Adding 1111 (15 in decimal) and 1111 (15 in decimal) in a 32-bit system may result in overflow an...read more

Effective paging techniques help reduce page faults, which are counted by tracking the number of times a page is accessed from disk.

• Implementing LRU (Least Recently Used) algorithm to replace the page that has not been used for the longest time.

• Using FIFO (First In, First Out) algorithm to replace the oldest page in memory.

• Utilizing optimal page replacement algorithm to replace the page that will not be used for the longest time in the future.

• Counting page faults by tracking ...read more

Design a system to store incoming characters in sorted manner and answer queries about character presence.

• Use a data structure like a balanced binary search tree to store characters in sorted order.

• Implement functions to insert characters into the tree and check for character presence.

• Optimize search queries by using binary search or tree traversal techniques.

• Consider edge cases like duplicate characters and handling special characters.

• Example: Insert 'a', 'c', 'b' -> Tree: [...read more

Static loading is done at compile time while dynamic loading is done at runtime in operating systems.

• Static loading involves loading all the necessary libraries and dependencies at compile time.

• Dynamic loading involves loading libraries and dependencies at runtime when they are needed.

• Static loading is faster but consumes more memory, while dynamic loading is slower but more memory efficient.

• Examples of static loading include C/C++ programs, while examples of dynamic loading ...read more

Types of polymorphism in OOP include compile-time polymorphism (method overloading) and runtime polymorphism (method overriding).

• Compile-time polymorphism is achieved through method overloading, where multiple methods have the same name but different parameters.

• Runtime polymorphism is achieved through method overriding, where a subclass provides a specific implementation of a method that is already defined in its superclass.

• Polymorphism allows objects of different classes to ...read more

malloc() allocates memory but does not initialize it, while calloc() allocates and initializes memory to zero.

• malloc() is used to allocate a block of memory of specified size, while calloc() is used to allocate and initialize a block of memory to zero.

• malloc() returns a pointer to the allocated memory block, while calloc() returns a pointer to the allocated and initialized memory block.

• Example: int *arr1 = (int*)malloc(5 * sizeof(int)); // allocates memory for 5 integers

• Examp...read more

A C program gets executed by first being compiled into machine code and then run by the operating system.

• C program is written in a text editor and saved with a .c extension.

• The program is then compiled using a compiler like GCC into machine code.

• The resulting executable file is loaded into memory by the operating system and executed.

• The program's instructions are carried out sequentially by the CPU.

• Once the program finishes, it returns an exit status to the operating system.

Banker's Algorithm is a resource allocation and deadlock avoidance algorithm used in operating systems.

• Used to avoid deadlock in a system by ensuring that resources are allocated safely.

• Works by keeping track of available resources and the maximum resources each process can request.

• If a request for resources puts the system in an unsafe state, it is denied.

• Example: Process A needs 3 instances of resource X, but only 2 are available, so the request is denied.

Advancements in industries have led to significant improvements in efficiency and productivity.

• Automation and robotics have reduced the need for manual labor

• Artificial intelligence has improved decision-making processes

• 3D printing has revolutionized manufacturing processes

• Internet of Things (IoT) has enabled real-time monitoring and control of industrial processes

A singleton class is a class that can only have one instance created at a time.

• Singleton classes are often used for managing resources that should only have one instance, such as a database connection.

• They are implemented by making the constructor private and providing a static method to access the single instance.

• Singleton classes can also be used for global state management in an application.

• In Java, the Singleton pattern can be implemented using the enum type.

• Singleton cla...read more

The question is about finding the area of a histogram and the Kth largest value.

• Calculate the area of the histogram by multiplying the width and height of each bar and summing them up.

• Find the Kth largest value by sorting the data and selecting the Kth element.

• The Kth largest value can also be found using a heap data structure.

• Example: Histogram area of [2, 3, 1, 4, 5] with bar width of 1 is 15. The 3rd largest value is 3.

Finding the Kth largest element in an array.

• Sort the array and return the Kth element from the end

• Use a max heap to keep track of the K largest elements

• Use quickselect algorithm to find the Kth largest element