Adjust Prices
Reported by candidates from Doordash's online assessment. Pattern, common pitfall, and the honest play if you blank under the timer.
You're taking the Doordash OA in March 2024 and just saw 'Adjust Prices' on the problem list. This is a straightforward array or hash-table manipulation problem that tests whether you can iterate through a data structure, apply a transformation rule, and return the result cleanly. It's not a trick question, but candidates often overcomplicate it or miss edge cases around null values, empty inputs, or the exact output format the system expects. StealthCoder will catch the pattern instantly if you blank on the structure.
Pattern and pitfall
The core task is almost certainly iterating through a collection of prices (array or hash-table) and applying a percentage-based adjustment or formula to each one. The gotcha is usually in the details: do you round or truncate? Do you mutate in place or return a new structure? Are there items with no price, or prices that shouldn't change? The pattern sits at the intersection of array manipulation and basic math. Most candidates solve it in under 10 minutes, but the common stumble is submitting before testing against edge cases like zero prices, very large percentages, or missing data. If you blank during the live OA, StealthCoder reads the exact input/output format and delivers the right approach in seconds.
StealthCoder is the hedge for the one pattern you didn't drill. It runs invisibly during the screen share.
You can drill Adjust Prices cold, or you can hedge it. StealthCoder runs invisibly during screen share and surfaces a working solution in under 2 seconds. The proctor sees the IDE. They don't see what's behind it. If you're reading this with an OA window open, you're who this was built for.
Get StealthCoderRelated leaked OAs
You've seen the question.
Make sure you actually pass Doordash's OA.
Doordash reuses patterns across OAs. If you're reading this with an OA window open, you're who this was built for. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Adjust Prices FAQ
Is this a hard problem?+
No. It's a warm-up. If you can loop, index, and apply arithmetic, you're 80% there. The difficulty is in the fine print: rounding rules, mutation vs. immutability, and handling nulls. Read the spec twice.
What's the trick?+
There usually isn't one. But candidates fail because they don't test negative prices, zero values, or the exact output format. Run through at least three test cases before submitting, including an edge case.
Do I need to sort or use a complex algorithm?+
No. It's a single pass through the data. If you're thinking about sorting, binary search, or dynamic programming, you're overthinking. Go linear.
How do I handle rounding?+
Check the problem statement. Most systems want Math.round(), Math.floor(), or explicit truncation. Test one sample and see which matches. Lock that in before you code the full solution.
Can I solve this in 48 hours if I've never seen it?+
Yes. Read similar LeetCode problems like Two Sum or Majority Element to brush up on array iteration. Then walk through the Doordash problem line by line. You don't need a study plan; you need to be awake.