Bloomberg coding interview prep
Strings, data structures, and 'now design the class for it'.
What the loop actually looks like
Bloomberg leans on solid data-structure work — strings, hash maps, heaps — and very often asks you to design a small class or API around the problem rather than just writing one function. Expect follow-ups that turn a function into a component.
What they reward
- String and hash-map manipulation
- Designing a small class/API around the problem
- Heaps and ordered structures
- Clear, extensible code
Patterns to drill first
Problems worth your time
In priority order. Open one to read the approach, or generate an interactive lesson and watch it run.
Min StackKeep a parallel stack of the minimum-so-far.
Medium
Group AnagramsGive every anagram the same canonical key.Medium
Top K Frequent ElementsCount, then select the k largest — a heap or bucket sort beats a full sort.Medium
Longest Substring Without Repeating CharactersGrow a window; when a repeat appears, shrink from the left past it.Medium
Valid ParenthesesA stack matches each closer to the most recent opener.Easy
Find Median from Data StreamBalance a max-heap of the low half against a min-heap of the high half.Hard
Daily TemperaturesA decreasing stack of indices resolves each 'next warmer day' exactly once.Medium
Tips specific to this loop
- — Practise turning a function into a class — `min-stack` is the archetype of this whole loop.
- — Think about the API you'd expose, not only the algorithm inside it.
- — String processing shows up constantly; don't neglect it for graph theory.
Drill these with interactive lessons
Generate a step-by-step lesson for any problem above — trace every variable and watch the pattern move until it clicks.
Start a free lessonPrepping for other companies
Our own editorial read on this loop, based on publicly reported experiences — not leaked or current question banks.