Chegg Coding Interview Questions
25 Chegg coding interview problems with full optimal solutions — 14 easy, 8 medium, 3 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Chegg interviewer values, and a FAQ section.
- #1easyfoundational
1. Two Sum
Find two indices in an array whose values sum to a target — Chegg uses this to filter for hash-map fluency on student-question lookup paths.
- #2easyfoundational
2. Valid Parentheses
Validate balanced brackets using a stack — Chegg uses this to check stack fluency for parsing student LaTeX answers.
- #3easyfoundational
3. Merge Two Sorted Lists
Splice two sorted linked lists into one — Chegg uses this to check pointer hygiene on ordered tutor-availability merges.
- #4easyfoundational
4. Remove Duplicates from Sorted Array
Dedupe a sorted array in place — Chegg uses this to check two-pointer skills for cleaning duplicate textbook-question rows.
- #5easyfoundational
5. Remove Element
Remove all occurrences of a value in place — Chegg uses this to validate two-pointer instincts on filter-content tasks.
- #6easyfoundational
6. Search Insert Position
Find the index where a target would be inserted in a sorted array — Chegg uses this to test binary-search rigor on textbook-page indexing.
- #7easyfoundational
7. Plus One
Increment a number represented by a digit array — Chegg uses this to check carry-propagation logic for tutor-session counter rollovers.
- #8easyfoundational
8. Merge Sorted Array
Merge two sorted arrays in place into the first — Chegg uses this to test reverse-pointer thinking on tutor-rating roll-ups.
- #9easyfoundational
9. Binary Tree Inorder Traversal
Return in-order values of a binary tree — Chegg uses this to check stack-based traversal on subject-taxonomy trees.
- #10easyfoundational
10. Same Tree
Check whether two binary trees are structurally identical with equal values — Chegg uses this to verify recursion fluency on duplicate-content checks.
- #11easyfoundational
11. Symmetric Tree
Detect mirror symmetry in a binary tree — Chegg uses this to test mirrored-recursion comfort on layout symmetry checks.
- #12easyfoundational
12. Maximum Depth of Binary Tree
Find the maximum depth of a binary tree — tests tree recursion fundamentals that underpin Chegg's content hierarchy traversal.
- #13easyfoundational
13. Balanced Binary Tree
Determine if a binary tree is height-balanced — tests ability to combine depth computation with tree validation, relevant to Chegg's content-tree consistency checks.
- #14easyfoundational
14. Path Sum
Check if a root-to-leaf path sums to a target — a foundational tree traversal problem Chegg uses to assess recursion and path-tracking skills.
- #15mediumfoundational
15. Number of Islands
Count connected components of '1's in a 2D grid — a graph traversal problem that mirrors Chegg's recommendation engine grouping related educational content.
- #16mediumfoundational
16. Course Schedule
Detect if all courses can be finished given prerequisites — directly mirrors Chegg's curriculum graph where course dependencies must be cycle-free.
- #17mediumfoundational
17. Implement Trie (Prefix Tree)
Build a trie supporting insert, search, and startsWith — directly maps to Chegg's search autocomplete and prefix-based textbook lookup features.
- #18mediumfoundational
18. Kth Largest Element in an Array
Find the kth largest element without full sorting — a selection algorithm Chegg applies when ranking educational content by relevance score.
- #19mediumfoundational
19. Word Search
Search for a word in a 2D character grid using DFS with backtracking — tests backtracking fundamentals Chegg applies to plagiarism detection across document matrices.
- #20mediumfoundational
20. Construct Binary Tree from Preorder and Inorder Traversal
Reconstruct a binary tree from two traversal orders — tests tree manipulation depth that Chegg uses for rebuilding content category hierarchies from index data.
- #21mediumfoundational
21. Longest Consecutive Sequence
Find the longest consecutive integer sequence in O(n) using a hash set — Chegg applies this pattern when detecting sequential gaps in student progress data.
- #22mediumfoundational
22. Word Break
Determine if a string can be segmented into dictionary words — Chegg uses this DP pattern for tokenizing educational query strings and segmenting compound subject names.
- #23hardfoundational
23. Trapping Rain Water
Compute total water trapped between histogram bars — a classic two-pointer hard that Chegg uses to assess whether candidates can reduce a prefix/suffix problem to O(1) space.
- #24hardfoundational
24. Median of Two Sorted Arrays
Find the median of two sorted arrays in O(log(m+n)) — a binary search hard that Chegg uses to test whether candidates can handle partitioned sorted data as arises in distributed search indexing.
- #25hardfoundational
25. Minimum Window Substring
Find the smallest substring of s containing all characters of t — a sliding window hard Chegg applies to substring matching in their document search and plagiarism detection pipelines.