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
29import importlib
# import csp_bitstring as csp_module
csp_module = importlib.import_module('csp_bitstring')
def recursive_backtracking(csp, assignment):
if csp_module.is_complete(csp, assignment):
return assignment
var = select_unassigned_variable(csp, assignment)
for value in csp_module.order_domain_values(csp, var):
if csp_module.is_consistent(csp, assignment, value):
assignment.append(value)
result = recursive_backtracking(csp, assignment)
if result is not None:
return result
del assignment[-1]
return None
def backtracking_search(csp, csp_impl):
global csp_module
csp_module = importlib.import_module(csp_impl)
return recursive_backtracking(csp, [])
def select_unassigned_variable(csp, assignment):
return len(assignment)