2.1 Linear and Binary Searching Algorithms

Define what is meant by the term 'algorithm'

• Step by step instructions or rules to solve a problem.
• Code for a specific task.

Which type of lists or data sets are linear searching algorithms used for?

• Unsorted lists or data sets
• Sorted lists or data sets

Which type of lists or data sets are binary searching algorithms used for?

• Unsorted lists or data sets
• Sorted lists or data sets

Select the best description to explain what a linear search algorithm is.

• Put the elements in order, check each item in turn.
• Put the elements in order, compare with the middle value, split the list in order and repeat.
• Elements do not need to be in order, check each item in turn.
• Elements do not need to be in order, compare to the middle value, split the list in order and repeat

Select the best description to explain what a binary search algorithm is.

• Put the elements in order, check each item in turn.

• Put the elements in order, compare with the middle value, split the list in order and repeat.

• Elements do not need to be in order, check each item in turn.

• Elements do not need to be in order, compare to the middle value, split the list in order and repeat

A linear search is to be performed on the list:
12   6   8  1  3
How many comparisons would it take to find number 1?

• 1
• 2
• 3
• 4

A binary search is to be performed on the list:
3  5  9  10  23
How many comparisons would it take to find number 9?

• 0-1
• 2-3
• 4-5
• I can't find the number 9

A binary search is to be performed on the list:
1  5  10  13  48  68  100  101
How many comparisons would it take to find number 101?

• 0-1
• 1-2
• 3-4
• 4-5

Describe an advantage of a linear search algorithm

• Data does not need to be in order.
• Performs well over large ordered lists.
• Can only work on an ordered list.  If unordered must use a linear search.
• Slow with large data sets.

Describe a disadvantage of a linear search algorithm

• Data does not need to be in order.
• Performs well over large ordered lists.
• Can only work on an ordered list.  If unordered must use a linear search.
• Slow with large data sets.