1. PFDS 11.2
Catenable Double-Ended
Queues
~ using implicit recursive slowdown ~
@rf0444

2. Simple Implementation
data Cat a
= Shallow (Deq a)
| Deep (Deq a) (Cat (Deq a)) (Deq a)

3. Simple Implementation
++

4. Simple Implementation
cons
snoc

5. Simple Implementation

6. Simple Implementation
( ++ )

7. Simple Implementation
( ++ )
再帰 O(min(log n1, log n2))

8. using compound elements
data Cat a
= Shallow (Deq a)
| Deep (Deq a) (Cat (Ele a)) (Deq a) (Cat (Ele a)) (Deq a)

9. using compound elements
data Ele a
= Simple (Deq a)
| Compound (Deq a) (Cat (Ele a)) (Deq a)

10. using compound elements
++

11. using compound elements

12. using compound elements

13. using compound elements
snoc cons

14. using compound elements

15. using compound elements

16. using compound elements
tail
1. f が 4 要素以上 f a m b r
2. a の先頭が Simple
3. a の先頭が Compound
4. a が空、b の先頭が Simple
5. a が空、b の先頭が Compound
6. a も b も空

17. using compound elements
tail (1)

18. using compound elements
tail (1)

19. using compound elements
tail (2)

20. using compound elements
tail (2)

21. using compound elements
tail (2)

22. using compound elements
tail (3)

23. using compound elements
tail (3)

24. using compound elements
tail (3)

25. using compound elements
tail (3)

26. using compound elements
tail (3)
++

27. using compound elements
tail (3)

28. using compound elements
tail (3)

29. using compound elements
tail (4)
空

30. using compound elements
tail (4)
空

31. using compound elements
tail (4)

32. using compound elements
tail (4)

33. using compound elements
tail (4)
空

34. using compound elements
tail (5)
空

35. using compound elements
tail (5)
空

36. using compound elements
tail (5)

37. using compound elements
tail (5)

38. using compound elements
tail (5)

39. using compound elements
tail (5)

40. using compound elements
tail (6)
空 空

41. using compound elements
tail (6)
空 空

42. using compound elements
tail (6)
＊どちらかのサイズが 3 以下なら、くっつけて Shallow

43. using compound elements
tail (6)

44. using compound elements
tail (6)
空 空