machine coding

Build a working system in 90–120 minutes

Some interviews skip the whiteboard. They give you a problem statement and 90–120 minutes, and say: build it, make it run, make it clean. These eight specs let you practise exactly that, with a judge that checks your code.

the round

What a machine-coding round is

In a machine-coding round you build a small, working system on your own laptop: a parking lot, a cache, a splitter. No database, no UI — just classes in memory.

Candidates' interview reports (community-reported, not official) describe this round at Indian product companies such as Flipkart: often 90 minutes, full working code in your own language, then a discussion where the interviewer reads your code and tries boundary cases.

You are marked on five things: working code, structure (can a new feature plug in?), the right data structures with their cost, edge cases, and readability. Working code comes first — a beautiful design that does not run scores low.

Every spec here gives you the exact Java API, an example session, a time plan and a judge with hidden tests. The reference solution stays hidden until you try.

sources: Flipkart Interview Experience | Set 50 (Off-campus) — a 90-minute machine coding round (GeeksforGeeks) ↗ (community-reported)

how to practise

One spec, one sitting

  1. Pick a spec. Read the brief and requirements twice. Write down your questions — in the real round, you would ask them.
  2. Start the timed mock. Follow the phases: clarify, design, core code, edge cases, polish.
  3. Write the code in the editor below the spec. Run checks the example session; Submit adds the hidden tests.
  4. Stuck for 15 minutes? Open one hint at a time. Then compare with the reference and mark yourself honestly on the rubric.
  5. Chalo, start with the parking lot. It is the most common first round, and the gentlest.

8 specs

Pick one and start the clock