FilesExpand file tree

 master

/

graph_search.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

76 lines (66 loc) · 2.28 KB

 master

/

graph_search.py

Copy path

Top

File metadata and controls

• Code
• Blame

76 lines (66 loc) · 2.28 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

class GraphSearch:

"""Graph search emulation in python, from source

http://www.python.org/doc/essays/graphs/"""

def __init__(self, graph):

self.graph = graph

def find_path(self, start, end, path=[]):

self.start = start

self.end = end

self.path = path

self.path += [self.start]

if self.start == self.end:

return self.path

if not self.graph.has_key(self.start):

return None

for node in self.graph[self.start]:

if node not in self.path:

newpath = self.find_path(node, self.end, self.path)

if newpath:

return newpath

return None

def find_all_path(self, start, end, path=[]):

self.start = start

self.end = end

self.path = path

self.path += [self.start]

if self.start == self.end:

return [self.path]

if not self.graph.has_key(self.start):

return []

paths = []

for node in self.graph[self.start]:

if node not in self.path:

newpaths = self.find_all_path(node, self.end, self.path)

for newpath in newpaths:

paths.append(newpath)

return paths

def find_shortest_path(self, start, end, path=[]):

self.start = start

self.end = end

self.path = path

self.path += [self.start]

if self.start == self.end:

return self.path

if not self.graph.has_key(self.start):

return None

shortest = None

for node in self.graph[self.start]:

if node not in self.path:

newpath = self.find_shortest_path(node, self.end, self.path)

if newpath:

if not shortest or len(newpath) < len(shortest):

shortest = newpath

return shortest

#example of graph usage

graph = {'A': ['B', 'C'],

'B': ['C', 'D'],

'C': ['D'],

'D': ['C'],

'E': ['F'],

'F': ['C']

}

#inistialization of new graph search object

graph1 = GraphSearch(graph)

print graph1.find_path('A', 'D')

print graph1.find_all_path('A', 'D')

print graph1.find_shortest_path('A', 'D')