1. A Series of Slides in 5 Parts Movement 3. IDFS
Maze Running in C Minor
A Series of Slides in 5 Parts
Movement 3. IDFS

2. MAX DEPTH: 1
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

3. MAX DEPTH: 1
AT: AB
STACK:
Note that since we are at depth 1, we do not push any neighbors of AB onto the stack.
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

4. MAX DEPTH: 2
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

5. MAX DEPTH: 2
AT: AB
STACK: BB AC
Note that we push all neighbors except for the node we just came from.
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

6. MAX DEPTH: 2
AT: BB
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

7. MAX DEPTH: 2
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

8. MAX DEPTH: 3
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

9. MAX DEPTH: 3
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

10. MAX DEPTH: 3
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

11. MAX DEPTH: 3
AT: CB
STACK: BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

12. MAX DEPTH: 3
AT: BA
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

13. MAX DEPTH: 3
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

14. MAX DEPTH: 4
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

15. MAX DEPTH: 4
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

16. MAX DEPTH: 4
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

17. MAX DEPTH: 4
AT: CB
STACK: DB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

18. MAX DEPTH: 4
AT: DB
STACK: BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

19. MAX DEPTH: 4
AT: BA
STACK: CA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

20. MAX DEPTH: 4
AT: CA
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

21. MAX DEPTH: 4
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

22. MAX DEPTH: 5
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

23. MAX DEPTH: 5
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

24. MAX DEPTH: 5
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

25. MAX DEPTH: 5
AT: CB
STACK: DB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

26. MAX DEPTH: 5
AT: DB
STACK: DE DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

27. MAX DEPTH: 5
AT: DE
STACK: DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

28. MAX DEPTH: 5
AT: DC
STACK: DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

29. MAX DEPTH: 5
AT: DA
STACK: BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

30. MAX DEPTH: 5
AT: BA
STACK: CA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

31. MAX DEPTH: 5
AT: CA
STACK: DA AC
Note that we push DA onto the stack even though we’ve already been there. This is an implementation of IDFS where no visit information is kept.
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

32. MAX DEPTH: 5
AT: DA
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

33. MAX DEPTH: 5
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

34. MAX DEPTH: 6
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

35. MAX DEPTH: 6
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

36. MAX DEPTH: 6
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

37. MAX DEPTH: 6
AT: CB
STACK: DB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

38. MAX DEPTH: 6
AT: DB
STACK: DE DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

39. MAX DEPTH: 6
AT: DE
STACK: EC EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

40. MAX DEPTH: 6
AT: EC
STACK: EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

41. MAX DEPTH: 6
AT: EA
STACK: DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

42. MAX DEPTH: 6
AT: DC
STACK: CC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

43. MAX DEPTH: 6
AT: CC
STACK: DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

44. MAX DEPTH: 6
AT: DA
STACK: CC BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

45. MAX DEPTH: 6
AT: CC
STACK: BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

46. MAX DEPTH: 6
AT: BA
STACK: CA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

47. MAX DEPTH: 6
AT: CA
STACK: DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

48. MAX DEPTH: 6
AT: DA
STACK: DB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

49. MAX DEPTH: 6
AT: DB
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

50. MAX DEPTH: 6
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

51. MAX DEPTH: 7
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

52. MAX DEPTH: 7
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

53. MAX DEPTH: 7
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

54. MAX DEPTH: 7
AT: CB
STACK: DB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

55. MAX DEPTH: 7
AT: DB
STACK: DE DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

56. MAX DEPTH: 7
AT: DE
STACK: EC EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

57. MAX DEPTH: 7
AT: EC
STACK: ED EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

58. MAX DEPTH: 7
AT: ED
STACK: EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

59. MAX DEPTH: 7
AT: EA
STACK: DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

60. MAX DEPTH: 7
AT: DC
STACK: CC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

61. MAX DEPTH: 7
AT: CC
STACK: CD BC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

62. MAX DEPTH: 7
AT: CD
STACK: BC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

63. MAX DEPTH: 7
AT: BC
STACK: DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

64. MAX DEPTH: 7
AT: DA
STACK: CC BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

65. MAX DEPTH: 7
AT: CC
STACK: BA BA AC
This is a rather comical situation.
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

66. MAX DEPTH: 7
AT: BA
STACK: BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

67. MAX DEPTH: 7
AT: BA
STACK: CA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

68. MAX DEPTH: 7
AT: CA
STACK: DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

69. MAX DEPTH: 7
AT: DA
STACK: DB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

70. MAX DEPTH: 7
AT: DB
STACK: EB DC CB DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

71. MAX DEPTH: 7
AT: EB
STACK: DC CB DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

72. MAX DEPTH: 7
AT: DC
STACK: CB DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

73. MAX DEPTH: 7
AT: CB
STACK: DA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

74. MAX DEPTH: 7
AT: DA
STACK: AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

75. MAX DEPTH: 6
AT: AC
STACK:
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

76. MAX DEPTH: 8
AT: AA
STACK: AB
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

77. MAX DEPTH: 8
AT: AB
STACK: BB AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

78. MAX DEPTH: 8
AT: BB
STACK: CB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

79. MAX DEPTH: 8
AT: CB
STACK: DB BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

80. MAX DEPTH: 8
AT: DB
STACK: DE DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

81. MAX DEPTH: 8
AT: DE
STACK: EC EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

82. MAX DEPTH: 8
AT: EC
STACK: ED EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

83. MAX DEPTH: 8
AT: ED
STACK: DD EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT

84. MAX DEPTH: 8
AT: DD
STACK: EA DC DA BA AC
KEY: GREEN – Start
RED – Exit
YELLOW – Visited on this iteration
Nodes are taken in the order: UP, LEFT, DOWN, RIGHT