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4,310 interview questions, answered.

Reference answers, what the interviewer is really testing, how it is graded, and the follow-ups that come next.

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205 questions

  1. 169Write a function to return all prime numbers up to a given number n.MediumCoding· Adobe, Apple
  2. 170Implement a queue using stacks.MediumCoding· Goldman Sachs
  3. 171Given a head node of a linked list, delete k-th node from the end of the list.MediumCoding· Meta
  4. 172Given the row and column, return the value at that position in Pascal's triangle.MediumCoding· Goldman Sachs
  5. 173Reverse a SentenceEasyCoding· Adobe, Apple
  6. 174Reverse a linked list.EasyCoding· Adobe, Apple
  7. 175Set Matrix ZeroesMediumCoding· Apple
  8. 176Infection spread simulation.MediumCoding· OpenAI
  9. 177Find the smallest missing element from a sorted array.EasyCodingTechnical· Meta
  10. 178Sort a doubly linked list using merge sort.MediumCodingTechnical· Meta
  11. 179Given an array of integers, print all subarrays that sum to zero.MediumCodingData· Meta
  12. 180Find the sum of all elements in a binary tree that fall within the range [low, high], where 'low' and 'high' are integers.MediumCoding· Meta
  13. 181Given a list of trades, iterate to return buy/sell pairs and overall profit.MediumCodingTechnical· Robinhood
  14. 182Valid ParenthesesEasyCoding· Apple, Booking.com
  15. 183Is this a valid palindrome?EasyCoding· Adobe, Apple
  16. 184Which sorting algorithms use divide and conquer?MediumCodingTechnical· Meta
  17. 185Write a program to count the frequency of each character in a given text file.EasyCodingTechnical· Andela
  18. 186Given two strings, return true if you could change 2 letters in the s string and return the goal string. If this isn't possible, return false.MediumCoding
  19. 187Copy a Spiral MatrixMediumCoding
  20. 188Find the Largest Smaller BST KeyHardCoding
  21. 189What are the issues that using hashmap on a multithreaded environment may cause? How would you deal with them?MediumCodingTechnical
  22. 190Explain how hash maps work.MediumCodingTechnical
  23. 191List the Differences Between Two StringsMediumCoding
  24. 192Shortest Cell PathMediumCoding