algorithmcrackers / interview-questions

List of all the Interview questions practiced from online resources and books

Interview-Questions

Contributions

• Anyone is welcome to add other Q&A here through a pull request
• Please make sure you upload to the right folder
• If you are unsure of its category, add it to Misc.
• If you dont have an answer, just add the question to a relevant README.md or raise an issue.

Thanks

• Thanks to Cracking the Coding Interview: The Sixth Edition by @gayle. She is an inspiration for newbie developers.
• We categorised all questions based on the book's index.
• https://github.com/andreis/interview
• Thanks to geeksforgeeks.com, leetcode.com and interviewbit for helping us learn through the process.

interview-questions's Issues

invert a binary tree

Possible solution of max Howel interview question? have to test it before integrating it.
http://www.quora.com/What-is-the-algorithmic-approach-to-invert-a-given-binary-tree

Add team blind's curated list

https://www.teamblind.com/post/New-Year-Gift---Curated-List-of-Top-75-LeetCode-Questions-to-Save-Your-Time-OaM1orEU

Array

• Two Sum Easy
• Best Time to Buy and Sell Stock Easy
• Contains Duplicate Easy
• Product of Array Except Self Medium
• Maximum Subarray Easy
• Maximum Product Subarray Medium
• Find Minimum in Rotated Sorted Array Medium
• Search in Rotated Sorted Array - https://leetcode.com/problems/search-in-rotated-sorted-array/
• 3Sum - https://leetcode.com/problems/3sum/
• Container With Most Water - https://leetcode.com/problems/container-with-most-water/

Binary

• Sum of Two Integers - https://leetcode.com/problems/sum-of-two-integers/
• Number of 1 Bits - https://leetcode.com/problems/number-of-1-bits/
• Counting Bits - https://leetcode.com/problems/counting-bits/
• Missing Number - https://leetcode.com/problems/missing-number/
• Reverse Bits - https://leetcode.com/problems/reverse-bits/

Dynamic Programming

• Climbing Stairs - https://leetcode.com/problems/climbing-stairs/
• Coin Change - https://leetcode.com/problems/coin-change/
• Longest Increasing Subsequence - https://leetcode.com/problems/longest-increasing-subsequence/
• Longest Common Subsequence - https://leetcode.com/problems/longest-common-subsequence/
• Word Break Problem - https://leetcode.com/problems/word-break/
• Combination Sum - https://leetcode.com/problems/combination-sum-iv/
• House Robber - https://leetcode.com/problems/house-robber/
• House Robber II - https://leetcode.com/problems/house-robber-ii/
• Decode Ways - https://leetcode.com/problems/decode-ways/
• Unique Paths - https://leetcode.com/problems/unique-paths/
• Jump Game - https://leetcode.com/problems/jump-game/

Graph

• Clone Graph - https://leetcode.com/problems/clone-graph/
• Course Schedule - https://leetcode.com/problems/course-schedule/
• Pacific Atlantic Water Flow - https://leetcode.com/problems/pacific-atlantic-water-flow/
• Number of Islands - https://leetcode.com/problems/number-of-islands/
• Longest Consecutive Sequence - https://leetcode.com/problems/longest-consecutive-sequence/
• Alien Dictionary (Leetcode Premium) - https://leetcode.com/problems/alien-dictionary/
• Graph Valid Tree (Leetcode Premium) - https://leetcode.com/problems/graph-valid-tree/
• Number of Connected Components in an Undirected Graph (Leetcode Premium) - https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/

Interval

• Insert Interval Hard
• Merge Intervals Medium
• Non-overlapping Intervals - https://leetcode.com/problems/non-overlapping-intervals/
• Meeting Rooms (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms/
• Meeting Rooms II (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms-ii/

Linked List

• Reverse a Linked List Easy
• Detect Cycle in a Linked List - https://leetcode.com/problems/linked-list-cycle/
• Merge Two Sorted Lists Easy
• Merge K Sorted Lists Hard
• Remove Nth Node From End Of List - https://leetcode.com/problems/remove-nth-node-from-end-of-list/
• Reorder List - https://leetcode.com/problems/reorder-list/

Matrix

• Set Matrix Zeroes Medium
• Spiral Matrix - https://leetcode.com/problems/spiral-matrix/
• Rotate Image Medium
• Word Search - https://leetcode.com/problems/word-search/

String

• Longest Substring Without Repeating Characters Medium
• Longest Repeating Character Replacement - https://leetcode.com/problems/longest-repeating-character-replacement/
• Minimum Window Substring - https://leetcode.com/problems/minimum-window-substring/
• Valid Anagram Easy
• Group Anagrams - https://leetcode.com/problems/group-anagrams/
• Valid Parentheses - https://leetcode.com/problems/valid-parentheses/
• Valid Palindrome - https://leetcode.com/problems/valid-palindrome/
• Longest Palindromic Substring - https://leetcode.com/problems/longest-palindromic-substring/
• Palindromic Substrings - https://leetcode.com/problems/palindromic-substrings/
• Encode and Decode Strings (Leetcode Premium) - https://leetcode.com/problems/encode-and-decode-strings/

Tree

• Maximum Depth of Binary Tree Easy
• Same Tree Easy
• Invert/Flip Binary Tree Easy
• Binary Tree Maximum Path Sum - https://leetcode.com/problems/binary-tree-maximum-path-sum/
• Binary Tree Level Order Traversal - https://leetcode.com/problems/binary-tree-level-order-traversal/
• Serialize and Deserialize Binary Tree - https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
• Subtree of Another Tree - https://leetcode.com/problems/subtree-of-another-tree/
• Construct Binary Tree from Preorder and Inorder Traversal - https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/
• Validate Binary Search Tree - https://leetcode.com/problems/validate-binary-search-tree/
• Kth Smallest Element in a BST - https://leetcode.com/problems/kth-smallest-element-in-a-bst/
• Lowest Common Ancestor of BST - https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
• Implement Trie (Prefix Tree) - https://leetcode.com/problems/implement-trie-prefix-tree/
• Add and Search Word - https://leetcode.com/problems/add-and-search-word-data-structure-design/
• Word Search II - https://leetcode.com/problems/word-search-ii/

Heap

• Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
• Top K Frequent Elements - https://leetcode.com/problems/top-k-frequent-elements/
• Find Median from Data Stream - https://leetcode.com/problems/find-median-from-data-stream/

Add this qn

http://stackoverflow.com/questions/17416233/data-structure-interview-find-max-number-in-array

What do you think is the run time of this function?

subsets.java
i think it is O(2^length * length)
what do u think?

Crazy hard question

• Smallest integer greater than zero which can not be created by summing any combination of the elements of the array

Same problem??

• http://stackoverflow.com/questions/21060873/minimum-sum-that-cant-be-obtained-from-a-set
• https://www.codechef.com/JAN14/problems/FRBSUM

can you add more comments to the individual functions, I dont understand what is happening

Regarding c95b578

Do Array and string folder be named as 01??

@santhoshvai

BST to Double linked list

reference answer link

Add README for codecon

Redefine structure of repo

lets redefine the structure of repository with all the questions in readme file and links in the corresponding files. by this way it would be easy for us to reference later.

Where can i add the link for competitive programming?

https://github.com/jaehyunp/stanfordacm

I find the above link to be useful for advanced interview preparations. I am not sure where to add it in the repo. Any suggestions?

Url shortener doesnt have any OO design. It just seems like a problem being solved.

https://github.com/AlgorithmCrackers/Interview-Questions/tree/master/07_Object-Oriented_Design/Url_shortner

Fits in someother category?

Add max-consecutive-ones-iii question

https://leetcode.com/problems/max-consecutive-ones-iii/

Asked in FB https://leetcode.com/discuss/interview-experience/488471/facebook-e4-jan-2020-offer

Trees and graphs has as extra src folder.

@santhoshvai

Use std <algorithm>

See if std::unique can be used for Remove Duplicates from Sorted Array problem, somehow.

Rename all the links in wiki since the model has been changed

check StringReverseInplace

I am getting runtime exception while running the code. but it looks correct to me.
Check and let me know where i am wrong.

Place questions in seperate folder named Questions

I have overwritten ur questions folder. Please redo it . @santhoshvai

redundancy check

1. what does this mean in 13th line
   stack[-1] += 1

2. is the code actually checking the redundancy check
   (a+b) - TRUE
   ((a+b)) - FALSE
   for second input would it give the correct error??

Interesting Dyn. Pgming question

You have an array of english words {cat, then, hen, end, dog}. Can you make out if the given sentence is a concatenation of only words from the array?

Cathen -> valid
thend -> not valid
cathenend -> valid

---

I think a trie can be used here. Like a suffix tree. What do you think? (google qn btw)

EDIT: GFG link

add to readme

for 6610190 update the questions to readme as well.

todo.md

the todo.md is more personal for you. It should rather be for a set of goals for the whole repo. Please delete it. I already made a public link in the root README.md to the todo list of wunderlist that we have.

Typo

In 44ded4c, minor typo for permutation.

P.S: Also, do document the code well. Your recent commits have been very good but they lack in documentation. When someone else to looks at your code, it takes a while to understand.

Add new Amazon SDE-1 questions from leetcode

See https://leetcode.com/discuss/interview-question/488887/amazon-final-interview-questions-sde1

* not required to solve
~ solve both iteratively and recursively

• Two Sum Easy
• Median of Two Sorted Arrays * (#4)
• Longest Palindromic Substring (#5)
• String to Integer (atoi) (#8)
• Integer to Roman (#12)
• Roman to Integer (#13)
• Valid Parentheses (#20)
• Merge K Sorted Lists (#23)
• Valid Sudoku (#36)
• Combination Sum (#39)
• Permutations (#46)
• Merge Intervals Medium
• Rotate List (#61)
• Word Search (#79)
• Validate Binary Search Tree(#98)
• Same Tree ~ (#100)
• Symmetric Tree ~ (#101)
• Binary Tree Level Order Traversal (#102)
• Convert Sorted List to Binary Search Tree (#109)
• Populating Next Right Pointers in Each Node (#116)
• Best Time to Buy and Sell Stock Easy
• Word Ladder II (#126)
• Word Ladder (#127)
• LRU Cache (#146)
• Min Stack (#155)
• Number of Islands (#200)
• Course Schedule (#207)
• Course Schedule II (#210)
• Integer to English Words (#273)
• Game of Life (#289)
• Find Median from Data Stream (#295)
• Longest Increasing Subsequence (#300)
• Design Tic-Tac-Toe (#348)
• Pacific Atlantic Water Flow (#417)
• Minesweeper (#529)
• Diameter of Binary Tree (#543)
• Reorganize String (#767)

REDO the topcoder repo

Please categorize it. Wiki is yet to be done.

Wiki basic questions has more java specific questions !!

We have come up with a way to sort questions specific to language in wiki.

https://github.com/AlgorithmCrackers/Interview-Questions/wiki/Basic-Qns

Finish the TODO

https://github.com/AlgorithmCrackers/Interview-Questions/tree/master/00_Arrays/MaximumSubArray

Kadane Algorithm

Time complexity

http://www.programcreek.com/2013/02/leetcode-longest-substring-without-repeating-characters-java/

see java solution 2

why is the time complexity O(n^3)?

JAVA: define and add annotations

lets add annotations for author name, date defined, details

https://docs.oracle.com/javase/tutorial/java/annotations/declaring.html

This can be a best practice for java programs.

Add questions from here

https://www.reddit.com/r/cscareerquestions/comments/3nzf1d/share_interview_questions_you_were_asked_this/