Capstone: Attack an Unseen Problem

The whole DSA shelf laid out as one flow: a judge that grades speed, a toolkit of structures, a set of strategies, and the process that reaches for each one in order.

Before you start. You’ve already met a judge for speed (Big-O), a shelf of structures to hold data, and a handful of strategies for attacking it, one lesson at a time. This lesson adds no new structure or trick; it’s the missing instruction sheet for reaching the right one when the problem in front of you has never been seen before.

The idea in 30 seconds

A plan can be completely correct and still be the wrong plan, if it needs a resource, memory or time, that you don’t have.
Reading the constraint first (how big, how much room) tells you the complexity you’re allowed before you’ve had a single idea - that’s what Big-O is actually for.
The obvious, correct plan first (brute force) is never a wasted step: it’s your baseline, and the only thing you can point at to ask “where is this wasting work” (the bottleneck).
Naming the bottleneck precisely - repeated storage, repeated search, repeated recomputation - tells you exactly which structure fixes it.
Verify the fix on your small hand example before you trust it, and only then write code.
The seven questions above work on any unseen problem, not just this one.

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