Define the comparator
Ascending value, frequency, or custom priority all produce different correct orders.
Sorting and Selection
6 chapters · 8 challenges · The Clockwork Market
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 does sorting really give you?
Sorting rearranges values under a comparison rule. The work is not only cosmetic: order creates boundaries that make searching, grouping, pairing, and duplicate handling predictable.
Think of a tournament leaderboard. Once every score is in order, ties sit together and the next rank is obvious. Without order, every question starts with another full search.
Each comparison moves the sequence toward one shared ordering rule.
Know the cost
General comparison sorts need O(n log n) time in the worst or average case.
Partition when enough
Selection problems often need only one side of the final order, not a fully sorted array.
What you will learn firstOrder the Gears
Begin the guided lesson Sort before chaos compounds
01
Comparison Sorting
0/3 completePractice comparison sorting through 3 visual expeditions.
02
Counting Sort
0/1 completePractice counting sort through 1 visual expedition.
03
Quickselect
0/1 completePractice quickselect through 1 visual expedition.
04
Custom Ordering
0/1 completePractice custom ordering through 2 visual expeditions.
05
Partitioning
0/1 completePractice partitioning 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.