Enumeration problems,
and the tell.
The constraints are small enough that you can simply try every candidate. 38 problems in the catalogue carry this tag, from first-week easy to interview hard.
Free to start. Running and submitting a solution never costs credits.
How the pattern actually works.
One mechanism, and the mistake that costs people the problem.
The tell. The constraints are small enough that you can simply try every candidate.
The mechanism. Work out the bound first. If n is 20 or the values are under a thousand, a double loop or a subset walk is the intended answer and anything cleverer is wasted effort.
What goes wrong. Not doing the arithmetic. Check the worst case against the time limit before you commit to it.
The ones asked most often.
By how often the catalogue records them being set, not by our opinion.
- Detect Pattern of Length M Repeated K or More TimesEasyasked at 1 companies
- Maximum Points in an Archery CompetitionMediumasked at 1 companies
- Largest Time for Given DigitsMediumasked at 1 companies
- Find the Integer Added to Array IIMediumasked at 1 companies
- Count Square Sum TriplesEasyasked at 1 companies
- Maximum Good People Based on StatementsHardasked at 1 companies
- Count Good TripletsEasyasked at 1 companies
- Maximum Area Rectangle With Point Constraints IMediumasked at 1 companies
- Minimum Moves to Capture The QueenMediumasked at 1 companies
- Number of Black BlocksMediumasked at 5 companies
Read it, watch it, then solve it.
The order that makes a pattern stick.
Everything in the app, in one place.
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DSA practice
Problems filed under the pattern that solves them, not a sheet.
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Build it inside the app, next to the work you practised.
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One score, and the axis you are weakest on.
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About enumeration problems.
Free to start, no card.
Start practisingHow do I know a problem is a enumeration problem?
The constraints are small enough that you can simply try every candidate.
How many enumeration problems should I solve?
Enough to stop needing the hint, which is usually ten to fifteen across the levels, not the whole list. The catalogue tags 38, split roughly 6 easy, 24 medium and 8 hard in the sample we show, so work up rather than across.
What goes wrong most often in enumeration problems?
Not doing the arithmetic. Check the worst case against the time limit before you commit to it.
Is practising by pattern better than a problem sheet?
A sheet tells you what to solve. A pattern tells you why those problems sit together, which is the part that carries over to the problem you have not seen. That is why the app files every problem under its pattern.