Order creates direction
A comparison must tell you which side can be discarded safely.
Binary Search
6 chapters · 10 challenges · The Split Peaks
Understand the idea, practise through play, then prove it in code. Choose your next quest below.
Visual introduction to this topic
Start here · 3 minute mental model
What is binary search?
Binary search uses a yes-or-no comparison to discard an impossible half of an ordered search space. The search space can be array indices or every feasible answer to a constraint.
Think of guessing a page number. Open the book near the middle. If the page you want is later, the entire first half is no longer useful.
Every valid decision must remove a whole region, not just one candidate.
State the boundary
Decide whether low and high are possible answers before writing the loop.
Search the answer
A monotonic feasible/not-feasible rule can be searched even without a stored array.
What you will learn firstThe Split Peak Signal
Begin the guided lesson Halve the only possible range
01
Exact Search
0/1 completePractice exact search through 1 visual expedition.
02
Boundary Search
0/3 completePractice boundary search through 4 visual expeditions.
03
Search On Answer
0/2 completePractice search on answer through 2 visual expeditions.
04
Rotated Arrays
0/2 completePractice rotated arrays through 2 visual expeditions.
05
Matrix Search
0/1 completePractice matrix search through 1 visual expedition.
06
Final challenge
0/1 completeCombine the skills from this world in a final challenge.
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This track is checked against the sources below. Visual traces still carry their own complete or guided coverage label, so unfinished explanations are not presented as complete executions.