Minimum Time to Repair Cars
A medium-tier problem at 60% community acceptance, tagged with Array, Binary Search. Reported in interviews at HashedIn and 1 others.
Minimum Time to Repair Cars is a medium-difficulty binary search problem that's been asked at HashedIn and Deloitte. You're given an array of repair rates and a number of cars, and you need to find the minimum time to fix them all. The catch: this looks like a straightforward math problem until you realize brute force will time out. Binary search on the answer space is the intended move, but most candidates don't see it coming. If this hits your live OA and you blank on the pattern, StealthCoder surfaces the solution invisibly.
Companies that ask "Minimum Time to Repair Cars"
Minimum Time to Repair Cars is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe trap is treating this as a greedy or simulation problem. You'll try to simulate the repair process or sort and assign cars, and it'll fail on large inputs. The real insight is binary searching on time itself. You pick a candidate time T, check if all cars can be repaired within T hours by simulating the work, then shrink or expand your search range. The binary search space runs from 1 to some maximum theoretical time. Common mistakes: off-by-one errors in the check function, not understanding how repair rates compound over time, and forgetting that you're searching for the minimum feasible time, not an index in an array. Array and Binary Search are the two core topics here, and combining them this way isn't intuitive without seeing the pattern first. StealthCoder's edge on this problem is massive if the pattern doesn't click in the first five minutes.
Pattern tags
You know the problem.
Make sure you actually pass it.
Minimum Time to Repair Cars recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Minimum Time to Repair Cars interview FAQ
Is this problem really asked at big companies?+
HashedIn and Deloitte have both reported asking it. It's a solid mid-level screening question because it catches engineers who can code but can't recognize binary search on continuous answer spaces. Not as common as sorting problems, but it shows up often enough to matter.
What's the trick everyone misses?+
People see 'repair cars' and think assignment or greedy scheduling. The trick is that time is continuous and searchable. You're not searching an array for a value. You're searching a time range for the minimum T where the answer becomes 'yes, this is possible.' That mental shift is the whole problem.
How do I verify a candidate time T works?+
For each repair rate in the array, calculate how many cars that rate can fix in T hours using integer division. Sum those counts. If the total is at least your car count, T works. This check function is O(n) and you'll run it O(log max_time) times, giving you your complexity.
Is this harder than typical binary search problems?+
Yes. Standard binary search runs on sorted arrays. This one runs on a continuous answer space. If you've only drilled array-index binary search, this feels like a different problem entirely. That's why acceptance is near 60 percent rather than 75 percent.
What are the failure points in the actual code?+
Off-by-one in your left and right bounds, forgetting to use integer division when calculating repair capacity, and setting your upper bound too low or too high. The check function itself is simple if you understand the math. Most fails are in the boundary logic.
Want the actual problem statement? View "Minimum Time to Repair Cars" on LeetCode →