-
Notifications
You must be signed in to change notification settings - Fork 0
/
TSP_Hamiltanion.py
75 lines (54 loc) · 1.59 KB
/
TSP_Hamiltanion.py
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
# Python3 program to implement traveling salesman
# problem using naive approach.
from sys import maxsize
V = 4
# implementation of traveling Salesman Problem
def travellingSalesmanProblem(graph, s):
# store all vertex apart from source vertex
vertex = []
for i in range(V):
if i != s:
vertex.append(i)
# store minimum weight Hamiltonian Cycle
min_path = maxsize
while True:
# store current Path weight(cost)
current_pathweight = 0
# compute current path weight
k = s
for i in range(len(vertex)):
current_pathweight += graph[k][vertex[i]]
k = vertex[i]
current_pathweight += graph[k][s]
# update minimum
min_path = min(min_path, current_pathweight)
if not next_permutation(vertex):
break
return min_path
# next_permutation implementation
def next_permutation(L):
n = len(L)
i = n - 2
while i >= 0 and L[i] >= L[i + 1]:
i -= 1
if i == -1:
return False
j = i + 1
while j < n and L[j] > L[i]:
j += 1
j -= 1
L[i], L[j] = L[j], L[i]
left = i + 1
right = n - 1
while left < right:
L[left], L[right] = L[right], L[left]
left += 1
right -= 1
return True
# Driver Code
if __name__ == "__main__":
# matrix representation of graph
graph = [[0, 10, 15, 20], [10, 0, 35, 25],
[15, 35, 0, 30], [20, 25, 30, 0]]
s = 0
print(travellingSalesmanProblem(graph, s))