Binary search

In this lesson, learners are introduced to binary search, the second and final searching algorithm they need to know about. They will go over the steps of carrying out a binary search and perform a binary search with playing cards and with a sample of data.

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Question 1

Question 2

Question 3

Question 4

Q1.What card would you need to search for, for the best-case scenario to occur?

Answer the questions below about performing a linear search on these cards:

1/4

Q2.What card would you need to search for, for the worst-case scenario to occur?

2/4

Q3.How many comparisons would it take to work out that a card wasn’t in the set of cards?

3/4

Q4.When carrying out the linear search, does the data need to be ordered?

4/4

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Question 1

Question 2

Question 3

Question 4

Q1.What card would you need to search for, for the best-case scenario to occur?

Answer the questions below about performing a linear search on these cards:

1/4

Q2.What card would you need to search for, for the worst-case scenario to occur?

2/4

Q3.How many comparisons would it take to work out that a card wasn’t in the set of cards?

3/4

Q4.When carrying out the linear search, does the data need to be ordered?

4/4

Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

  • Click "Close Video"
  • Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

Quiz:

Binary Search

This quiz is to assess your learning from this lesson. Read the description below and select which term it is referring to:

Question 1

Question 2

Question 3

Question 4

Q1.When carrying out the binary search, does the data need to be ordered?

1/4

Q2.With each comparison, the binary search algorithm eliminates how of the data.

2/4

Q3.If the midpoint item is less than than the search item, do you change the range to focus on the items after or before the midpoint

3/4

Q4.When finding the item in the middle of the range (the midpoint item). If there is an even number of items, which item do you select?

4/4

Quiz:

Binary Search

This quiz is to assess your learning from this lesson. Read the description below and select which term it is referring to:

Question 1

Question 2

Question 3

Question 4

Q1.When carrying out the binary search, does the data need to be ordered?

1/4

Q2.With each comparison, the binary search algorithm eliminates how of the data.

2/4

Q3.If the midpoint item is less than than the search item, do you change the range to focus on the items after or before the midpoint

3/4

Q4.When finding the item in the middle of the range (the midpoint item). If there is an even number of items, which item do you select?

4/4

Lesson summary: Binary search

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