-
Notifications
You must be signed in to change notification settings - Fork 0
/
08b_solution.pl
118 lines (98 loc) · 3.56 KB
/
08b_solution.pl
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
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
# vim: set filetype=prolog
# How to run:
# * load with SWI prolog interpreter (others might work, not tested),
# e.g.: swipl -s 08b_solution.pl
# * issue: run(Solution).
run(Solution) :-
read_patterns(Patterns),
solve_all(Patterns, Outputs),
!, % assume unique solution for each puzzle
sum_numbers(Outputs, Solution).
read_patterns(Patterns) :-
read_file_to_string("08input.txt", String, []),
split_string(String, "\n", "\n", Lines),
lines_to_patterns(Lines, Patterns).
lines_to_patterns([], []).
lines_to_patterns([Line|T], [Patterns|NT]) :-
line_to_patterns(Line, Patterns),
lines_to_patterns(T, NT).
line_to_patterns(Line, [InputPatterns, OutputPatterns]) :-
split_string(Line, "|", " ", [InputString, OutputString]),
segment_to_patterns(InputString, InputPatterns),
segment_to_patterns(OutputString, OutputPatterns).
segment_to_patterns(String, Patterns) :-
split_string(String, " ", " ", PatternStrings),
parse_patterns(PatternStrings, Patterns).
parse_patterns([], []).
parse_patterns([H|T], [NH|NT]) :-
parse_pattern(H, NH),
parse_patterns(T, NT).
parse_pattern(String, Pattern) :-
string_chars(String, Pattern).
%%%%%%%
sum_numbers(Outputs, Solution) :-
sum_numbers_ctr(Outputs, 0, Solution).
sum_numbers_ctr([], C, C).
sum_numbers_ctr([H|T], C, Solution) :-
get_as_number(H, Num),
NewC is C + Num,
sum_numbers_ctr(T, NewC, Solution).
% this is very roundabout, maybe there is a better way...
get_as_number(L, Num) :-
atomic_list_concat(L, Atom),
atom_string(Atom, String),
number_string(Num, String).
%%%%%%%
solve_all([], []).
solve_all([H|T], [NH|NT]) :-
[InputPatterns, OutputPatterns] = H,
solve_single(InputPatterns, OutputPatterns, NH),
solve_all(T, NT).
solve_single(InputPatterns, OutputPatterns, OutputDigits) :-
match_wires(InputPatterns, Wires),
match_outputs(OutputPatterns, Wires, OutputDigits).
% returns a permutation of wires such that:
% * the first element is the wire that goes to signal a
% * the second element is the wire that goes to signal b
% * etc.
match_wires(Patterns, Wires) :-
permutation([a,b,c,d,e,f,g], Wires),
match_patterns(Patterns, Wires).
match_patterns([], _).
match_patterns([H|T], Wires) :-
match_pattern(H, Wires),
match_patterns(T, Wires).
match_pattern(Pattern, Wires) :-
% match signals A-G to wires
[A, B, C, D, E, F, G] = Wires,
(
permutation(Pattern, [A, B, C, E, F, G]); % 0
permutation(Pattern, [C, F]); % 1
permutation(Pattern, [A, C, D, E, G]); % 2
permutation(Pattern, [A, C, D, F, G]); % 3
permutation(Pattern, [B, C, D, F]); % 4
permutation(Pattern, [A, B, D, F, G]); % 5
permutation(Pattern, [A, B, D, E, F, G]); % 6
permutation(Pattern, [A, C, F]); % ]7
permutation(Pattern, [A, B, C, D, E, F, G]); % 8
permutation(Pattern, [A, B, C, D, F, G]) % 9
).
match_outputs([], _, []).
match_outputs([H|T], Wires, [NH|NT]) :-
match_output(H, Wires, NH),
match_outputs(T, Wires, NT).
match_output(Pattern, Wires, Digit) :-
% match signals A-G to wires
[A, B, C, D, E, F, G] = Wires,
(
(Digit = 0, permutation(Pattern, [A, B, C, E, F, G]));
(Digit = 1, permutation(Pattern, [C, F]));
(Digit = 2, permutation(Pattern, [A, C, D, E, G]));
(Digit = 3, permutation(Pattern, [A, C, D, F, G]));
(Digit = 4, permutation(Pattern, [B, C, D, F]));
(Digit = 5, permutation(Pattern, [A, B, D, F, G]));
(Digit = 6, permutation(Pattern, [A, B, D, E, F, G]));
(Digit = 7, permutation(Pattern, [A, C, F]));
(Digit = 8, permutation(Pattern, [A, B, C, D, E, F, G]));
(Digit = 9, permutation(Pattern, [A, B, C, D, F, G]))
).