Sorting

1. Sorting

2. What does sorting mean? Sorting means to arrange the data in a certain order.

3. How to interchange the content of two glasses of water ?

4. The previous movie clip shows the concept of swapping. In fact, swapping means to interchange of two items.

5. VariableX VariableY temporary To swap the content of variable X and Y, we need to employ a temporary variable. X Y

6. VariableX VariableY temporary Assign the content in variableX to the temporary variable. Temporary := VariableX; X Y X

7. VariableX VariableY temporary Assign the content in variableY to the variableX. VariableX := VariableY; Y Y X

8. VariableX VariableY temporary Assign the content in the temporary variable to the variableY. VariableY := temporary; Y X X

9. VariableX VariableY temporary The contents of variable X and Y are swapped. Y X X

10. What is bubble Sort? Bubble sort is a sorting algorithm. The idea of bubble sort is to compare all adjacent (相鄰) elements in the array successively (遂一地) and swap them if they are not in right order.

11. To illustrate the concept of bubble sort, we are going to sort a list of 4 items in ascending order step by step.

12. 84 Score [1] 74 Score [2] 97 Score [3] 16 Score [4] Sorting in ascending order

13. 84 Score [1] 74 Score [2] 97 Score [3] 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap

14. 84 74 Score [1] 74 84 Score [2] 97 97 Score [3] 16 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap

15. 84 74 Score [1] 74 84 Score [2] 97 97 Score [3] 16 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap 84 < 97 No Swap

16. 84 74 74 Score [1] 74 84 84 Score [2] 97 97 97 Score [3] 16 16 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap 84 < 97 No Swap

17. 84 74 74 Score [1] 84 84 74 Score [2] 97 97 97 Score [3] 16 16 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap 84 < 97 No Swap 97 > 16 Swap

18. 84 74 74 74 Score [1] 84 84 84 74 Score [2] 97 97 97 16 Score [3] 16 16 97 16 Score [4] Sorting in ascending order Pass 1 84 > 74 Swap 84 < 97 No Swap 97 > 16 Swap

19. 84 74 74 Score [1] 84 84 74 Score [2] 97 97 97 Score [3] 16 16 16 Score [4] Sorting in ascending order Pass 1 74 84 16 97 97 is placed in the correct position

20. 74 Score [1] 84 Score [2] 16 Score [3] 97 Score [4] Sorting in ascending order Pass 2

21. 74 Score [1] 84 Score [2] 16 Score [3] 97 Score [4] Sorting in ascending order Pass 2

22. 74 74 Score [1] 84 84 Score [2] 16 16 Score [3] 97 97 Score [4] Sorting in ascending order Pass 2 74 < 84 No Swap

23. 74 74 Score [1] 84 84 Score [2] 16 16 Score [3] 97 97 Score [4] Sorting in ascending order Pass 2 74 < 84 No Swap

24. 74 74 74 Score [1] 16 84 84 Score [2] 16 16 84 Score [3] 97 97 97 Score [4] Sorting in ascending order Pass 2 74 < 84 No Swap 84 > 16 Swap

25. 74 74 Score [1] 84 84 Score [2] 16 16 Score [3] 97 97 Score [4] Sorting in ascending order Pass 2 74 16 84 97 84 is placed in the correct position

26. 74 Score [1] 16 Score [2] 84 Score [3] 97 Score [4] Sorting in ascending order Pass 3

27. 74 Score [1] 16 Score [2] 84 Score [3] 97 Score [4] Sorting in ascending order Pass 3

28. 74 16 Score [1] 16 74 Score [2] 84 84 Score [3] 97 97 Score [4] Sorting in ascending order Pass 3 74 > 16 Swap

29. 74 Score [1] 16 Score [2] 84 Score [3] 97 Score [4] Sorting in ascending order Pass 3 16 74 84 97 74 > 16 Swap

30. 74 Score [1] 16 Score [2] 84 Score [3] 97 Score [4] Sorting in ascending order Pass 3 16 74 84 97 All elements are sorted.

31. Advantage and Disadvantage of Bubble Sort: Advantage - simple to implement. Disadvantage - slow in run time.