CARS24 coding interview
questions, leaked.
8 problems reported across recent CARS24 interviews. Top patterns: hash table, array, string. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
CARS24 is asking 8 problems, and 7 of them are medium difficulty. One easy problem won't save you. The real pattern here is hash-table and array problems stacked together, with string and design mixed in. You're looking at pattern-recognition under pressure, not algorithmic wizardry. Most candidates see "hash-table" and think "just use a dictionary." That's where they fail. CARS24 wants you to see the problem, know the structure, and move fast. If you freeze on a hash-table or array design question mid-assessment, StealthCoder runs invisibly during screen share and surfaces a working solution in seconds. You don't need to have solved every variant. You need a hedge.
Top problems at CARS24
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Time Based Key-Value Store | MEDIUM | 100.0 | 49% | Hash Table · String · Binary Search |
| 02 | Online Election | MEDIUM | 94.5 | 52% | Array · Hash Table · Binary Search |
| 03 | Open the Lock | MEDIUM | 87.4 | 61% | Array · Hash Table · String |
| 04 | Rabbits in Forest | MEDIUM | 87.4 | 58% | Array · Hash Table · Math |
| 05 | Counter | EASY | 77.3 | 82% | |
| 06 | Bulls and Cows | MEDIUM | 77.3 | 51% | Hash Table · String · Counting |
| 07 | Merge Intervals | MEDIUM | 77.3 | 49% | Array · Sorting |
| 08 | House Robber | MEDIUM | 77.3 | 52% | Array · Dynamic Programming |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual CARS24 OA. The proctor cannot see it. Screen share cannot detect it. Made for the engineer who has done the work but might still blank with a webcam pointed at him.
Get StealthCoder- hash table5 · 63%
- array5 · 63%
- string3 · 38%
- binary search2 · 25%
- design2 · 25%
- breadth first search1 · 13%
- math1 · 13%
- greedy1 · 13%
- counting1 · 13%
- sorting1 · 13%
The distribution is brutal but predictable. Hash-table appears in 5 of 8 problems, array in 5 of 8. They're not testing breadth, they're testing depth in two core skills. String problems and design questions appear alongside them, meaning you're solving hash-table problems that also demand string manipulation or system thinking. Binary search shows up twice, usually paired with hash-table or design (see Time Based Key-Value Store and Online Election). The single hard problem doesn't exist, but don't get overconfident. Medium difficulty at CARS24 means the twist is in the data structure choice and the edge cases, not the algorithm. String and counting problems (Bulls and Cows) require careful state tracking. When you hit a medium-difficulty hash-table problem with a string or design component, that's where StealthCoder becomes your real advantage. You can't practice every variation in a week.
Companies with similar patterns
If you prepped for CARS24, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass CARS24.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Made for the engineer who has done the work but might still blank with a webcam pointed at him. Works on HackerRank, CodeSignal, CoderPad, and Karat.
CARS24 interview FAQ
Should I study hash-table first for CARS24?+
Yes. Hash-table problems appear in 5 of 8 total problems and overlap heavily with array and string questions. Start with hash-table fundamentals: when to use it, collision handling, and state management. Then drill problems like Time Based Key-Value Store and Rabbits in Forest to see how hash-table pairs with design and math concepts.
Is one easy problem enough preparation?+
No. Counter is the only easy problem. The remaining 7 are medium, and they're not stepping stones. Treat the easy as a warm-up only. Spend 80% of prep time on medium-difficulty hash-table and array problems, especially those combining two or three topics at once.
How much time should I spend on design and binary search?+
Design and binary search each appear in 2 problems, often paired with hash-table. Don't ignore them, but don't let them dominate early prep. Solve Time Based Key-Value Store and Online Election to see how design and binary search integrate into hash-table problems. That teaches more than isolated design drills.
What's the difference between CARS24 problems and standard medium-difficulty problems?+
CARS24's medium problems stack multiple topics: Open the Lock combines array, hash-table, string, and BFS. Bulls and Cows mixes hash-table, string, and counting. Single-topic problems are rare. Prep by solving complete problems, not isolated concepts.
If I don't recognize a pattern on the assessment, what do I do?+
Hash-table or array pattern recognition is make-or-break. If you blank on a medium-difficulty hash-table variant you haven't seen, a real-time backup that runs invisibly during screen share gives you a working solution and buys you time to move forward or think through edge cases instead of rewriting from scratch.