1

Depth First Search

0

1

2

3

4

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

2

Depth First Search

0

1

2

3

4

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

flow()

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

3

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

4

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

5

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

mark down right left up

dfs(1, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

6

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

mark down right left up

dfs(1, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

7

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

mark down right left up

dfs(1, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

8

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

mark down right left up

dfs(1, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

9

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

mark down right left up

dfs(1, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

10

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

11

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

12

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 0)

0 1 2 3 4

open site

blocked site

reachable from top via open sites

13

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)open site

blocked site

reachable from top via open sites

14

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)open site

blocked site

reachable from top via open sites

15

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

open site

blocked site

reachable from top via open sites

16

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

open site

blocked site

reachable from top via open sites

17

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

open site

blocked site

reachable from top via open sites

18

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

open site

blocked site

reachable from top via open sites

19

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

open site

blocked site

reachable from top via open sites

20

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

open site

blocked site

reachable from top via open sites

21

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(3, 2)

open site

blocked site

reachable from top via open sites

22

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(3, 2)

open site

blocked site

reachable from top via open sites

23

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(3, 2)

open site

blocked site

reachable from top via open sites

24

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(3, 2)

open site

blocked site

reachable from top via open sites

25

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(3, 2)

open site

blocked site

reachable from top via open sites

26

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

open site

blocked site

reachable from top via open sites

27

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

open site

blocked site

reachable from top via open sites

28

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(2, 1)

open site

blocked site

reachable from top via open sites

29

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(2, 1)

open site

blocked site

reachable from top via open sites

30

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(2, 1)

open site

blocked site

reachable from top via open sites

31

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(2, 1)

open site

blocked site

reachable from top via open sites

32

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

mark down right left up

dfs(2, 1)

open site

blocked site

reachable from top via open sites

33

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(2, 2)

open site

blocked site

reachable from top via open sites

34

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

open site

blocked site

reachable from top via open sites

35

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

open site

blocked site

reachable from top via open sites

36

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

open site

blocked site

reachable from top via open sites

37

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

open site

blocked site

reachable from top via open sites

38

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

open site

blocked site

reachable from top via open sites

39

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

open site

blocked site

reachable from top via open sites

40

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

open site

blocked site

reachable from top via open sites

41

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

open site

blocked site

reachable from top via open sites

42

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

open site

blocked site

reachable from top via open sites

43

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

open site

blocked site

reachable from top via open sites

44

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

mark down right left up

dfs(4, 4)open site

blocked site

reachable from top via open sites

45

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

mark down right left up

dfs(4, 4)open site

blocked site

reachable from top via open sites

46

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

mark down right left up

dfs(4, 4)open site

blocked site

reachable from top via open sites

47

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

mark down right left up

dfs(4, 4)open site

blocked site

reachable from top via open sites

48

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

mark down right left up

dfs(4, 4)open site

blocked site

reachable from top via open sites

49

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

open site

blocked site

reachable from top via open sites

50

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

open site

blocked site

reachable from top via open sites

51

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

mark down right left up

dfs(3, 4)

open site

blocked site

reachable from top via open sites

52

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

open site

blocked site

reachable from top via open sites

53

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

open site

blocked site

reachable from top via open sites

54

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

mark down right left up

dfs(2, 4)

open site

blocked site

reachable from top via open sites

55

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

open site

blocked site

reachable from top via open sites

56

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

open site

blocked site

reachable from top via open sites

57

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

mark down right left up

dfs(1, 4)

open site

blocked site

reachable from top via open sites

58

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

open site

blocked site

reachable from top via open sites

59

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

mark down right left up

dfs(1, 3)

open site

blocked site

reachable from top via open sites

60

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

open site

blocked site

reachable from top via open sites

61

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

mark down right left up

dfs(1, 2)

open site

blocked site

reachable from top via open sites

62

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

open site

blocked site

reachable from top via open sites

63

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

open site

blocked site

reachable from top via open sites

64

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)

mark down right left up

dfs(0, 2)

open site

blocked site

reachable from top via open sites

65

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)open site

blocked site

reachable from top via open sites

66

dfs(0, 0) dfs(0, 1) dfs(0, 2) dfs(0, 3) dfs(0, 4)

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)open site

blocked site

reachable from top via open sites

67

Depth First Search

0

1

2

3

4

0 1 2 3 4

flow()

dfs(0, 0)open site

blocked site

reachable from top via open sites