New Year Gift - Curated List of Top 75 LeetCode Questions to Save Your Time

Facebook / Eng tech lead
Dec 30, 2018 69 Comments

New Year Gift to every fellow time-constrained engineer out there looking for a job, here's a list of the best LeetCode questions that teach you core concepts and techniques for each category/type of problems! Many other LeetCode questions are a mash of the techniques from these individual questions. I used this list in my last job hunt to only do the important questions.

Good luck and Happy New Year!

Array

- Two Sum - https://leetcode.com/problems/two-sum/
- Best Time to Buy and Sell Stock - https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
- Contains Duplicate - https://leetcode.com/problems/contains-duplicate/
- Product of Array Except Self - https://leetcode.com/problems/product-of-array-except-self/
- Maximum Subarray - https://leetcode.com/problems/maximum-subarray/
- Maximum Product Subarray - https://leetcode.com/problems/maximum-product-subarray/
- Find Minimum in Rotated Sorted Array - https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/
- 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 -
- 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 - https://leetcode.com/problems/insert-interval/
- Merge Intervals - https://leetcode.com/problems/merge-intervals/
- 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 - https://leetcode.com/problems/reverse-linked-list/
- Detect Cycle in a Linked List - https://leetcode.com/problems/linked-list-cycle/
- Merge Two Sorted Lists - https://leetcode.com/problems/merge-two-sorted-lists/
- Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
- 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 - https://leetcode.com/problems/set-matrix-zeroes/
- Spiral Matrix - https://leetcode.com/problems/spiral-matrix/
- Rotate Image - https://leetcode.com/problems/rotate-image/
- Word Search - https://leetcode.com/problems/word-search/

---

String

- Longest Substring Without Repeating Characters - https://leetcode.com/problems/longest-substring-without-repeating-characters/
- Longest Repeating Character Replacement - https://leetcode.com/problems/longest-repeating-character-replacement/
- Minimum Window Substring - https://leetcode.com/problems/minimum-window-substring/
- Valid Anagram - https://leetcode.com/problems/valid-anagram/
- 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 - https://leetcode.com/problems/maximum-depth-of-binary-tree/
- Same Tree - https://leetcode.com/problems/same-tree/
- Invert/Flip Binary Tree - https://leetcode.com/problems/invert-binary-tree/
- 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/

You're welcome!

comments

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TOP 69 Comments
  • Apple
    apeAndApe

    Apple

    PRE
    Google, Uber
    apeAndApemore
    What is the basis of this short list? How did you come up with the list? What is the criteria?
    Dec 31, 2018 2
    • Facebook / Eng tech lead
      OP
      I did 400-500 LC questions last time and distilled the most useful questions from my experience into this list.
      Dec 31, 2018
    • Apple
      apeAndApe

      Apple

      PRE
      Google, Uber
      apeAndApemore
      Ok, thank you
      Dec 31, 2018
  • Vertivco / Eng
    FastPapuan

    Vertivco Eng

    PRE
    Youtube, American Bureau of Shipping, Facebook
    FastPapuanmore
    Sir.
    Sir.
    You forgot Cherry Picking #741.
    Dec 30, 2018 0
  • New 2xtc
    In Leetcode list form: https://leetcode.com/list/xoqag3yj/
    May 3 1
    • eBay / Eng gkhldncjs
      but there are only 74 of them :(

      never mind, I don't have a premium account
      Aug 13
  • Cisco jgudvruv
    Let the grind begin
    Dec 30, 2018 0
  • New srjJ86
    Have done about 500 and I approve this!
    Jul 24 9
    • Microsoft leetlleet
      Thanks for the reply. How about coding round? I am at 120 and trying to figure out how many will be good enough. Did you feel that you are passing the coding rounds with flying color?
      Aug 3
    • New srjJ86
      If you are not unlucky they dont ask very tricky questions, at least I havent got. Mostly mediums were asked. If you can solve mediums comfortably in each category hopefully you are good to go. Fankly if tricky questions are asked where you need special tricks to solve it, its higly unlikely someone will be able to solve it if not seen that before, specially considering interview pressure situation.
      Aug 4
    • New srjJ86
      One more thing I can add. Nothing can beat practice. The more you practice the more you will see the patterns. You just need to see the pattern to nail a problem and it comes from practice. Solving X amount gives that exposure, more you solve its better.
      Aug 4
    • Microsoft leetlleet
      Thanks!
      Aug 4
    • Microsoft whatchado
      Hey Srj, have you decided where to go? Any update (lesson learned type)?
      Aug 24
  • Aurora bystander!
    Nerds are orgasming!
    Peace bro...
    Dec 30, 2018 0
  • Google euBx84
    This legit af OP. Now I can just practice these few before interviewing lol. You the real tech lead!
    Dec 31, 2018 1
    • New / Eng
      brazilian

      New Eng

      BIO
      I'm Brazilian.
      brazilianmore
      Did you received offer from Google because of this list?
      Sep 22
  • Mentor Graphics vAjo15
    You are the hero that blind don’t deserve
    Dec 30, 2018 0
  • Microsoft 🐟FishyFish
    Thank you! I’m brushing up algo for google interview
    Dec 31, 2018 7
    • Oracle / Eng NUkX62
      +1
      Jan 8
    • Oath
      nerdsRule!

      Oath

      BIO
      hit me up if you’re hiring. I am strong in algorithms and decent at development skills. Will try my best to get you your referral bonus, hate Verizon!
      nerdsRule!more
      enough for G if you deeply understand how to solve each of the above problems, although I’ve heard EMEA and APAC area G interviews are harder so might not be enough for those

      P.S : passed HC recently , above list covers all areas
      Feb 17
    • Oracle blahbl
      Google APAC is fucking crazy! I cracked it a couple of years ago and hands down the toughest interview I’ve ever faced.
      Feb 17
    • Dematic / Eng Larry Cook
      What’s APAC?
      Aug 16
    • New tbTO28
      Asia Pacific
      Aug 29
  • Ericsson / Eng FriedFish1
    Saved.. you’re a god 🙏
    Dec 30, 2018 0
  • Is this good enough for Facebook onsite?
    Jul 26 3
    • Intel gtfo2019
      No
      Jul 26
    • Yes !
      I received an offer from FB!
      Aug 13
    • Microsoft whatchado
      Hey blindboy congrats! May I ask you how many you solved in total (lifetime)? How many tagged FB questions? Or did you only solve the ones here?
      Aug 24
  • Groupon randomusr0
    I created a CSV out of it - https://pastebin.com/zneJ2NbD
    Apr 30 0
  • Microsoft / Eng Sbhdu
    Great effort OP.
    Imo most of these are already covered in the leetcode's most liked questions list and the amazon list.
    Dec 31, 2018 2
    • Facebook / Eng tech lead
      OP
      They must have been inspired by my list. My list was published and open sourced since a year ago ;)
      Dec 31, 2018
    • Microsoft jefgfi
      Can u give us the link to it op?
      Dec 31, 2018
  • Microsoft meanwhile
    Are you the techlead in YouTube?
    Aug 3 1
    • Jetblack
      faangpaani

      Jetblack

      PRE
      Oscar
      faangpaanimore
      🤣
      Aug 3
  • Comcast onlytroll
    If this helps me get through to FANG+, I'm going to hunt you down, and buy you a round 🍻kind stranger!
    Aug 24 0
  • Microsoft PNlg17
    Anyone used these to get senior (l5) at google? Are they too easy?
    Apr 30 0
  • PayPal jLeT47
    Thanks op to compile the list. But there are 75 questions mentioned in the list. Did you miss pasting the remaining 25?
    Feb 17 0
  • New / Eng Za4rt8
    Thanks OP for the gift.
    Jan 7 0
  • Microsoft UMbR3
    You're my Jesus
    Dec 31, 2018 0