Gnome sort

1. Gnome Sort
Hup university
20-02-2018

2. Gnome Sort
• The algorithm always finds the first place
where two adjacent elements are in the
wrong order, and swaps them. It takes
advantage of the fact that performing a swap
can introduce a new out-of-order adjacent
pair only next to the two swapped elements.
It does not assume that elements forward of
the current position are sorted, so it only
needs to check the position directly previous
to the swapped elements.

3. Algorithm
• procedure gnomeSort(a[]):
• pos := 0
• while pos < length(a):
• if (pos == 0 or a[pos] >= a[pos-1]):
• pos := pos + 1
• else:
• swap a[pos] and a[pos-1]
• pos := pos - 1

4. 40<9? No , exchange then Backward
Is 40 < 9?
No
Swap (40,9)
No Backward

5. 9<40? Yes, Forward
Is 9 < 40?
Yes
Go Forward

6. 40<3? No, exchange Backward
Is 40 < 3?
No
Swap (40,3)
Go Backward

7. 9< 3? No, exchange backward
Is 9 < 3?
No,
swap(9,3)
Go Backward

8. 3<9? Yes, Forward
Is 3 <9?
Yes
Go Forward

9. 9< 40? Yes, Forward
Is 9 < 40?
Yes
Go Forward

10. 40<7? No, exchange Backward
Is 40 < 7?
No ,
swap(40,7)
Go Backward

11. 9<7 ?No, exchange backward
Is 9 < 7?
No, swap(9,7)
Go Backward

12. 3<7 ? Yes, Forward
Is 3 < 7?
Yes
Go Forward

13. 7<9 ? Yes, Forward
Is 7 < 9?
Yes
Go Forward

14. 9 <40? Yes, Forward
Is 9 < 40?
Yes
Go Forward

15. 40<50? Yes, Forward
Is 40 < 50?
Yes
Go Forward

16. 50< 23? No, exchange Backward
Is 50 < 23?
No
swap(50,23)
Go Backward

17. 40<23? No, exchange Backward
Is 40 < 23?
No
Swap(40,23)
Go Backward

18. 9<23? Yes, Forward
Is 9 < 23?
Yes
Go Forward

19. 23>40? Yes, Forward
Is 23 < 40?
Yes
Go Forward

20. 40<50? Yes, Forward
Is 40 < 50?
Yes
Go Forward

21. 50<5?No, exchange Backward
Is 50 < 5?
No
Swap(50,5)
Go Backward

22. 40<5?No, exchange Backward
Is 40 < 5?
No
Swap(40,5)
Go Backward

23. 23<5?No, exchange Backward
Is 23 < 5?
No
Swap(23,5)
Go Backward

24. 9<5? No, exchange Backward
Is 9 < 5?
Yes
Go Forward

25. 7<5? No exchange Backward
Is 7 < 5?
No
Swap(7,5)
Go Backward

26. 3<5? Yes , Forward
Is 3 < 5?
Yes
Go Forward

27. 5<7? Yes, Forward
Is 5 < 7?
Yes
Go Forward

28. 7<9? Yes, Forward
Is 7 < 9?
Yes
Go Forward

29. 9<23? Yes, Forward
Is 9 < 23?
Yes
Go Forward

30. 23<40? Yes, Forward
Is 23 < 40?
Yes
Go Forward

31. 40<50?Yes, Forward
Is 40 < 50?
Yes
Go Forward

32. 50<12? No, exchange Backward
Is 50 < 12?
No
Swap(50,12)
Go Backward

33. 40<12? No, exchange Backward
Is 40 < 12?
No
Swap(40,12)
Go Backward

34. 23<12? No, exchange Backward
Is 23 < 12?
No
Swap(23,12)
Go Backward

35. 9<12? Yes, Forward
Is 9 < 12?
Yes
Go Forward

36. 12<23? Yes, Forward
Is 12 < 23?
Yes
Go Forward

37. 23<40? Yes Forward
Is 23 < 40?
Yes
Go Forward

38. 40<50? Yes, Forward
Is 40 < 50?
Yes
Go Forward

39. End
At the end Rock
No check