2.1 Algorithms

2.1 Algorithms

1. Computational Thinking

   • The use of computers to solve problems

2. Abstraction

   • Representing 'Real World' Problems using a computer using variables and symbols and removing unnecessary elements from the problem.

3. Decomposition

   • breaking down a large problem into smaller more manageable sub-problems
     • Easier problems
     • they can be created independent of the other problems
     • they can be tested independently
     • Can be combined to produce the full problem

4. Algorithmic Thinking

   • Identifying the steps involved in solving a problem

5. Linear Search

   • Each item in the list is checked in order
     • Does not need to be in order
       • check the first value
         • Move to and check the next value
           • Repeat until you have checked all the elements and not found the value you are looking for

6. Binary Search

   • An ordered list is divided in 2 with each comparison
     • Needs to be in order
     • Take the middle value
     • Compare to the value you are looking for
     • If it is larger than the one you are looking for - take the values to the left of the middle value
       • Opposite direction if the value is smaller

7. Bubble Sort

   • Moving through a list repeatedly, swapping elements that are in the wrong order

8. Merge Sort

   • A list is split into individual lists, these are then combined (2 lists at a time)
   • 2.) Split a list into individual lists 2.) Merge the lists in pairs, putting the smallest first 3.) Merge the lists 4.) Keep merging until it is in order

9. List

   • A set of data

10. Merging lists

    • 1.) Split all elements into individual lists. 2.) Compare the first element in both lists 3.) put the smallest into a new list 4.) Compare the next element of list 1 with the second element of the 2nd list 5.) put the smallest into a new list 6.) repeat until merged

11. Insertion sort

    • Each items is take in turn, compare to the items in a sorted list and placed into the correct position

12. Ordered List

    • Elements are arranged in sequence

13. Unordered List

    • Unarranged elements

14. Algorithm

    • the series of steps to solve a problem or perform an action

15. Flowchart

    • A diagram that shows the inputs, and outputs and processes
    • Can be used to represent an Algorithm
    • It shows the data that is input and output
    • It shows the processes (Actions) that take place
    • it shows the decisions and repetitions that take place
    • Lines are used to show the flow of control
    • Set shapes are used to represent different functions

16. Process

    • An action that takes place

17. Pseudocode

    • Simplified programming code that is not language specific, used to design algorithms.
    • Means 'Fake Code'
    • Its part way between English sentences, and programming code
    • It is language neutural

18. Dry Run

    • Walking through an algorithm which sample data, running each step manually.

19. Trace table

    • A table that follows the values of variables to check for accuracy

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