Indeed Coding Interview Questions
25 Indeed coding interview problems with full optimal solutions — 16 easy, 6 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 Indeed interviewer values, and a FAQ section.
- #1easyfoundational
1. Two Sum
Find two array indices whose values sum to a target — Indeed's warmup before scaling to candidate-to-job matching where complement lookups dominate.
- #2easyfoundational
2. Valid Parentheses
Validate that bracket pairs are properly nested and closed — Indeed uses it to gauge stack fluency before resume-parser and search-query syntax problems.
- #3easyfoundational
3. Merge Two Sorted Lists
Merge two sorted linked lists into one sorted list — the linked-list merge that underpins Indeed's job-feed combination from multiple syndication sources.
- #4easyfoundational
4. Remove Duplicates from Sorted Array
Compact a sorted array in place so each unique value appears once — Indeed's dedup warmup before scaling to duplicate job-posting suppression.
- #5easyfoundational
5. Remove Element
Strip all instances of a target value from an array in place and return the new length — Indeed uses it to test in-place filtering before sponsored-listing removal problems.
- #6easyfoundational
6. Search Insert Position
Find the index to insert a target into a sorted array — Indeed's binary-search warmup before ranked-results bisection problems.
- #7easyfoundational
7. Plus One
Increment a number represented as a digit array — Indeed's carry-handling warmup before pagination-counter and impression-id problems.
- #8easyfoundational
8. Merge Sorted Array
Merge two sorted arrays in place — Indeed's two-pointer pattern that maps directly to combining ranked job lists from multiple shards.
- #9easyfoundational
9. Binary Tree Inorder Traversal
Return the inorder traversal of a binary tree — Indeed's tree-walk warmup that maps to traversing taxonomy nodes in a job-category tree.
- #10easyfoundational
10. Same Tree
Check if two binary trees are structurally and value-wise identical — Indeed uses it as a building block for duplicate-posting tree comparison.
- #11easyfoundational
11. Symmetric Tree
Decide whether a binary tree is a mirror of itself — Indeed's mirror-recursion warmup before bidirectional graph matching problems.
- #12easyfoundational
12. Maximum Depth of Binary Tree
Compute the maximum depth of a binary tree — Indeed's recursive-base-case warmup before facet-tree depth limits in category browse.
- #13easyfoundational
13. Balanced Binary Tree
Determine whether a binary tree is height-balanced — mirrors how Indeed validates hierarchical job-category trees before indexing them.
- #14easyfoundational
14. Path Sum
Check whether a root-to-leaf path in a binary tree sums to a target — a building block for Indeed's skill-weight aggregation in job-fit scoring.
- #15easyfoundational
15. Pascal's Triangle
Generate the first numRows rows of Pascal's triangle — tests iterative 2D array construction that mirrors Indeed's incremental ranking coefficient tables.
- #16easyfoundational
16. Single Number
Find the element that appears exactly once in an array where every other element appears twice — the XOR trick appears in Indeed's deduplication pipelines for job listings.
- #17mediumfoundational
17. Longest Substring Without Repeating Characters
Find the length of the longest substring without repeating characters — the sliding window pattern powers Indeed's query tokenizer deduplication.
- #18mediumfoundational
18. Group Anagrams
Cluster strings that are anagrams of each other — directly models how Indeed groups near-duplicate job titles before deduplication and canonical-name resolution.
- #19mediumfoundational
19. Number of Islands
Count connected land regions in a grid — Indeed uses this pattern to identify clusters of related job listings in geographic heat-map generation.
- #20mediumfoundational
20. Product of Array Except Self
Compute each element's product of all other elements without using division — a prefix/suffix scan Indeed applies to confidence-score normalization across job recommendations.
- #21mediumfoundational
21. Top K Frequent Elements
Return the k most frequent elements — a core primitive in Indeed's trending search query and popular job-title surfacing pipelines.
- #22mediumfoundational
22. Subarray Sum Equals K
Count contiguous subarrays whose sum equals k — the prefix-sum hash map approach models Indeed's click-window aggregation in A/B test signal computation.
- #23hardfoundational
23. Trapping Rain Water
Calculate how much water is trapped between elevation bars — Indeed uses this two-pointer pattern in capacity-planning and bandwidth-allocation simulations.
- #24hardfoundational
24. Minimum Window Substring
Find the smallest window in string s containing all characters of string t — Indeed applies this sliding-window pattern to relevance window extraction in resume-to-job-description matching.
- #25hardfoundational
25. Largest Rectangle in Histogram
Find the largest rectangular area in a histogram — Indeed's infrastructure team uses monotonic-stack reasoning for memory-region packing in their large-scale index builder.