Searching, sorting and efficiency: Representations and decisions

≈ 36 min

Searching, sorting and efficiency: Representations and decisions

Searching answers where an item is; sorting answers what order items should appear in. Linear search checks items one by one. Binary search repeatedly halves a candidate range, but it is correct only when the values are already sorted by the same rule.

Learning move. In this lesson, choose a diagram, table, trace or model that makes the decision visible.

Worked example. Find a learner ID in an unsorted sign-in list with linear search. Find a surname in an alphabetised register by comparing to the middle entry and discarding the half where the name cannot be.

Which statement best reflects this lesson's sorted precondition?

Binary search requires values already sorted using the same comparison rule.

Use a vague rule and trust the first result.

Ignore boundary cases and hidden assumptions.

Choose a tool before stating the problem.

Write the key term for this lesson: sorted precondition.

A school system needs a reliable next step. Which choice is most defensible for this topic?

Sort repeated-look-up data once, then use binary search only when that preparation is justified.

Store an unexplained guess and call it evidence.

Give every account unrestricted access.

Hide the error so the report looks complete.

A learner can repeat a definition from Searching, sorting and efficiency: Representations and decisions. Which next task gives stronger evidence of mastery?

Apply the idea to an unfamiliar boundary, error or decision and justify the choice.

Repeat the lesson title without using the concept.

Choose the first option before reading the scenario.

Hide an unexpected result so the answer appears tidy.