En anglais

Start at the front, stop at the match

Computing · Programming · ages 15-16

Name ______________________ Date ____________

Hunting 57 in 8, 21, 57, 64 and 90, how many checks run before it stops?
Answer: ______________
Where does a linear search begin checking?
- At the middle
- At the front
- At the end
Linear search still works when the data is jumbled.
Circle one: True False
A name hunt across 45 names misses at every slot. How many checks ran?
Answer: ______________
Hunting 50 in 8, 21, 57, 64 and 90, what comes back?
- -1
- 0
- 5
On a nonempty list, when does the best case strike?
- When the target sits last
- When the list is empty
- When the target is first
A 600-item list roughly doubles a 300-item list. What happens to worst-case checks?
- They stay exactly equal
- They halve at once
- They roughly double too
A friend claims you must sort before a linear search. What is wrong?
- Sorting is harmful to every search
- Sorting is needless, since each item is asked in turn
- Sorting deletes the target

Answer key

For grown-ups. Fold this page away before handing over the rest.

3 · Two misses then a match make three checks. The match sits in seat 2.
At the front · The hunt opens at the first item and walks forward.
True · It asks each item in turn, so order never matters.
45 · The worst case checks each of the 45 names once.
-1 · No item matches, so all five checks run and -1 reports that the target is absent.
When the target is first · On a nonempty list, one check is the fewest a hunt can take.
They roughly double too · Worst-case checks track list size in a straight line.
Sorting is needless, since each item is asked in turn · Order never matters here, so sorting buys nothing.