10+ Computer Scientist Interview Questions and Answers

Determine if a path exists in a matrix filled with directional indicators from a start to an end point.

• Use Depth-First Search (DFS) or Breadth-First Search (BFS) to explore paths.

• Check if the current position is within matrix bounds and not visited.

• Example: In a 2D grid, 'U' means up, 'D' means down, 'L' means left, 'R' means right.

• Track visited nodes to avoid cycles and infinite loops.

Given an array of integers, find if a subarray exists whose sum equals to k.

• Use a hashmap to store the prefix sum and its frequency.

• Iterate through the array and check if the difference between current prefix sum and k exists in the hashmap.

• If it exists, then a subarray with sum k exists.

• Time complexity: O(n), Space complexity: O(n).

To break a linked list into two lists, we can traverse the list and add nodes to respective lists based on their value.

• Traverse the linked list and add nodes to positive or negative list based on their value

• Create two empty lists for positive and negative nodes

• Iterate through the linked list and add nodes to respective lists

• Join the two lists at the end to get the final result

Merge K-Sorted Linked List

• Create a min heap of size k

• Insert the first element of each linked list into the heap

• Pop the minimum element from the heap and add it to the result list

• Insert the next element from the linked list of the popped element into the heap

• Repeat until all elements are processed

Calculate the minimum number of movie theatres needed based on start times and durations of movies.

• Sort the movies by their start times.

• Use a priority queue to track end times of movies currently being shown.

• For each movie, check if it can fit in an existing theatre or if a new one is needed.

• Example: Start times [1, 2, 3] and durations [2, 2, 2] require 2 theatres.

The react application needs to be completed with given functionalities.

• Implement state management using Redux or Context API

• Create components for different sections of the application

• Fetch data from an API and display it in the application

• Add routing using React Router for navigation

• Implement form handling for user input

BFS (Breadth-First Search) is a graph traversal algorithm that explores all the vertices of a graph in breadth-first order.

• Create a queue to store the visited vertices

• Start with the initial vertex and enqueue it

• While the queue is not empty, dequeue a vertex and mark it as visited

• Enqueue all the adjacent vertices of the dequeued vertex that are not yet visited

• Repeat until the queue is empty

An autocomplete system predicts user input based on a given prefix using a trie data structure.

• Use a Trie (prefix tree) to store words for efficient prefix searching.

• Insert words into the Trie, e.g., 'apple', 'app', 'application'.

• Implement a search function that retrieves suggestions based on the prefix.

• Return suggestions as an array of strings, e.g., ['apple', 'app', 'application'] for prefix 'app'.

• Consider using a priority queue to rank suggestions based on frequency or rec...read more

The four pillars of OOP are encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling of data and methods into a single unit (class) to hide implementation details.

• Inheritance: Ability of a class to inherit properties and behaviors from another class.

• Polymorphism: Ability of objects of different classes to be treated as objects of a common superclass.

• Abstraction: Simplifying complex systems by breaking them down into smaller, more manageable units.

The Three Sum problem involves finding unique triplets in an array that sum to zero.

• Use a sorted array to simplify the search for triplets.

• Utilize a two-pointer technique to find pairs that complement a fixed element.

• Example: For array [-1, 0, 1, 2, -1, -4], the triplets are [-1, -1, 2], [-1, 0, 1].

• Avoid duplicates by skipping over repeated elements in the sorted array.