What is the Practice Hub?

A searchable question bank of every coding interview problem in the Grokking library, stripped of lessons and coding pattern scaffolding so you can go straight to solving. Each problem has its own URL, a lean editor, and automatic grading.

Searching, filtering, and viewing problem statements is free for everyone. Running code, saving progress, and unlocking your correctness, runtime, and time-to-solve stats require a free Educative account.

How are problems tagged by company?

Tags come from aggregated interview reports and are refreshed monthly. A company tag means the problem, or a close variant, was reported in that company’s loop within the last two years.

What happens when I click Start practice?

The current filtered list becomes a practice session. Problems are served one at a time in the Coding Interview Preparation editor, and your results are written back to this list so you can see what to revisit.

Practice the exact problems top companies ask.

Search 2,800+ real coding interview problems. Filter by company, role, topic, and difficulty, then solve in a lean editor right in your browser.

2,800+Problems

312Companies

49Topics

30Roles

Nov 14Last updated

All problems

The full question bank. Search, filter, then hit Practice. Your progress shows up as you go.

204 problems

1Valid PalindromeBlind 75Grind 75
Two PointersEasy
23SumBlind 75Grind 75
Two PointersMedium
3Remove nth Node from End of ListBlind 75
Two PointersMedium
4Sort ColorsGrind 75
Two PointersMedium
5Reverse Words in a String
Two PointersMedium
6Lowest Common Ancestor of a Binary Tree III
Two PointersMedium
7Reverse String
Two PointersEasy
8Intersection of Two Linked Lists
Two PointersEasy
9String Compression
Two PointersMedium
10Rotate Array
Two PointersMedium
11Remove Duplicates from Sorted Array
Two PointersEasy
12Reverse Vowels of a String
Two PointersEasy
13Compare Version Numbers
Two PointersMedium
14Move Zeroes
Two PointersEasy
15Remove Duplicates from Sorted List II
Two PointersMedium
16Two Sum II - Input Array Is Sorted
Two PointersMedium
17One Edit Distance
Two PointersMedium
18Happy Number
Fast and Slow PointersEasy
19Middle of the Linked ListGrind 75
Fast and Slow PointersEasy
20Sliding Window Maximum
Sliding WindowHard
21Longest Substring without Repeating CharactersBlind 75Grind 75
Sliding WindowMedium
22Minimum Size Subarray Sum
Sliding WindowMedium
23Best Time to Buy and Sell StockBlind 75Grind 75
Sliding WindowEasy
24Substring with Concatenation of All Words
Sliding WindowHard
25Permutation in String
Sliding WindowMedium
26Find the Index of the First Occurrence in a String
Sliding WindowEasy
27Subarray Product Less Than K
Sliding WindowMedium
28Longest Substring with At Most K Distinct Characters
Sliding WindowMedium
29Merge IntervalsBlind 75Grind 75
IntervalsMedium
30Insert IntervalBlind 75Grind 75
IntervalsMedium
31Interval List Intersections
IntervalsMedium
32Employee Free Time
IntervalsHard
33Task SchedulerGrind 75
IntervalsMedium
34Meeting Rooms IIBlind 75
IntervalsMedium
35Reverse Linked ListBlind 75Grind 75
In-Place Manipulation of a Linked ListEasy
36Reverse Nodes in k-Group
In-Place Manipulation of a Linked ListHard
37Reverse Linked List II
In-Place Manipulation of a Linked ListMedium
38Reorder ListBlind 75
In-Place Manipulation of a Linked ListMedium
39Remove Linked List Elements
In-Place Manipulation of a Linked ListEasy
40Odd Even Linked List
In-Place Manipulation of a Linked ListMedium
41Find Median from a Data StreamBlind 75Grind 75
Two HeapsHard
42Meeting Rooms III
Two HeapsHard
43Last Stone Weight
Two HeapsEasy
44Merge Sorted Array
K-way MergeEasy
45Merge K Sorted ListsBlind 75Grind 75
K-way MergeHard
46Kth Smallest Element in a Sorted Matrix
K-way MergeMedium
47K Closest Points to OriginGrind 75
Top K ElementsMedium
48Top K Frequent ElementsBlind 75
Top K ElementsMedium
49Kth Largest Element in an Array
Top K ElementsMedium
50Minimum Cost to Hire K Workers
Top K ElementsHard

50 of 204

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EM at Google

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Software Engineer @ Microsoft

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