101 lines
4.0 KiB
Perl
101 lines
4.0 KiB
Perl
|
:- use_module(library(pio)).
|
||
|
|
:- use_module(library(dcg/basics)).
|
||
|
|
:- op(700, xfx, [supports, is_way_above]).
|
||
|
|
:- initialization(main, main).
|
||
|
|
|
||
|
|
main([FileName|_]) :-
|
||
|
|
input(FileName, Bricks),
|
||
|
|
stack(Bricks, Stacked),
|
||
|
|
support_listing(Stacked, LookDown, LookUp),
|
||
|
|
max_member(MaxN-_-_-_, Bricks),
|
||
|
|
findall(N, (between(0, MaxN, N), can_remove(N, LookDown, LookUp)), Ns),
|
||
|
|
length(Ns, Answer),
|
||
|
|
write(Answer), nl.
|
||
|
|
|
||
|
|
can_remove(N, LookDown, LookUp) :-
|
||
|
|
BeingSupporteds = LookUp.N,
|
||
|
|
write(N), write("("), write(LookDown.N), write(") supporting "),
|
||
|
|
write(BeingSupporteds), nl,
|
||
|
|
maplist(supported_by_more_than_one(LookDown), BeingSupporteds).
|
||
|
|
|
||
|
|
supported_by_more_than_one(LookDown, N) :- LookDown.N > 1.
|
||
|
|
|
||
|
|
% StackedBricks is sorted by decreasing top edge
|
||
|
|
support_listing(StackedBricks, SupportedCount, SupportingMap) :-
|
||
|
|
findall(
|
||
|
|
N=SupportedListLen,
|
||
|
|
( append(_, [Brick1|Belows], StackedBricks),
|
||
|
|
supported_by(Brick1, Belows, SupportedList),
|
||
|
|
length(SupportedList, SupportedListLen),
|
||
|
|
Brick1 = N-_-_-_),
|
||
|
|
SupportedLists),
|
||
|
|
SupportedCount = brick{}.put(SupportedLists),
|
||
|
|
sort(2, @=<, StackedBricks, StackSortedByBottoms),
|
||
|
|
findall(
|
||
|
|
M=SupportingList,
|
||
|
|
( append(_, [Brick2|Aboves], StackSortedByBottoms),
|
||
|
|
supporting(Brick2, Aboves, SupportingList),
|
||
|
|
Brick2 = M-_-_-_),
|
||
|
|
SupportingLists),
|
||
|
|
SupportingMap = brick{}.put(SupportingLists).
|
||
|
|
|
||
|
|
% Aboves need to be sorted by increasing bot edge
|
||
|
|
supporting(_Brick, [], []).
|
||
|
|
supporting(Brick, [Above|_], []) :- Above is_way_above Brick, !.
|
||
|
|
supporting(Brick, [Above|Aboves], Supportings) :-
|
||
|
|
supporting(Brick, Aboves, NextSupportings),
|
||
|
|
( Brick supports Above
|
||
|
|
-> Above = N-_-_-_, Supportings = [N|NextSupportings]
|
||
|
|
; Supportings = NextSupportings).
|
||
|
|
|
||
|
|
% Belows need to be sorted decreasing by top edge
|
||
|
|
supported_by(_Brick, [], []).
|
||
|
|
supported_by(Brick, [Below|_], []) :- Brick is_way_above Below, !.
|
||
|
|
supported_by(Brick, [Below|Belows], SupportedBy) :-
|
||
|
|
supported_by(Brick, Belows, NextSupportedBy),
|
||
|
|
( Below supports Brick
|
||
|
|
-> Below = N-_-_-_, SupportedBy = [N|NextSupportedBy]
|
||
|
|
; SupportedBy = NextSupportedBy).
|
||
|
|
|
||
|
|
is_way_above(_-_-_-(Z2bot-_), _-_-_-(_-Z1top)) :- Z2bot > Z1top + 1.
|
||
|
|
supports(Brick1, Brick2) :-
|
||
|
|
overlap(Brick1, Brick2),
|
||
|
|
Brick1 = _-_-_-(_-Z1top), Brick2 = _-_-_-(Z2bot-_), Z2bot =:= Z1top + 1.
|
||
|
|
|
||
|
|
stack(Bricks, StackedBricks) :-
|
||
|
|
empty_heap(H0), foldl(stack1, Bricks, H0, Heap),
|
||
|
|
heap_to_list(Heap, HeapList),
|
||
|
|
maplist([_-Brick, Brick]>>(true), HeapList, StackedBricks).
|
||
|
|
|
||
|
|
stack1(Brick, Heap, NewHeap) :-
|
||
|
|
( max_of_heap(Heap, OldZtop, OldTop), overlap(Brick, OldTop)
|
||
|
|
; empty_heap(Heap), OldZtop is 0),
|
||
|
|
Brick = N-X-Y-(Zbot-Ztop),
|
||
|
|
NewZbot is OldZtop + 1, NewZtop is NewZbot + (Ztop - Zbot),
|
||
|
|
add_to_maxheap(Heap, NewZtop, N-X-Y-(NewZbot-NewZtop), NewHeap),
|
||
|
|
!.
|
||
|
|
stack1(Brick, Heap, NewHeap) :-
|
||
|
|
get_from_maxheap(Heap, LastZtop, LastTopBrick, HeapWithoutTop),
|
||
|
|
stack1(Brick, HeapWithoutTop, NewHeapWithoutTop),
|
||
|
|
add_to_maxheap(NewHeapWithoutTop, LastZtop, LastTopBrick, NewHeap).
|
||
|
|
|
||
|
|
overlap(_-(Xa1-Xa2)-(Ya1-Ya2)-_, _-(Xb1-Xb2)-(Yb1-Yb2)-_) :-
|
||
|
|
Xa1 =< Xb2, Xa2 >= Xb1, Ya1 =< Yb2, Ya2 >= Yb1.
|
||
|
|
|
||
|
|
% input parsing stuff below. Brick indexing is for debugging.
|
||
|
|
input(FileName, SortedBricks) :-
|
||
|
|
phrase_from_file(bricks(0, Bricks), FileName),
|
||
|
|
sort(2, @=<, Bricks, SortedBricks).
|
||
|
|
bricks(_, []) --> eos, !.
|
||
|
|
bricks(N, [Line|Lines]) --> {Next is N+1}, brick(N, Line), bricks(Next, Lines).
|
||
|
|
brick(N, N-(X1-X2)-(Y1-Y2)-(Z1-Z2)) -->
|
||
|
|
number(X1), ",", number(Y1), ",", number(Z1), "~",
|
||
|
|
number(X2), ",", number(Y2), ",", number(Z2), "\n".
|
||
|
|
|
||
|
|
% maxheap wrapper. PriX = -Pri, which is the Ztop
|
||
|
|
max_of_heap(H, Pri, Key) :- min_of_heap(H, PriX, Key), Pri is -PriX.
|
||
|
|
add_to_maxheap(H0, Pri, Key, H) :- PriX is -Pri, add_to_heap(H0, PriX, Key, H).
|
||
|
|
get_from_maxheap(H0, Pri, Key, H) :- get_from_heap(H0, PriX, Key, H), Pri is -PriX.
|
||
|
|
|
||
|
|
% Can probably do 2 maps, one by top edges and one by bottom edges and lookup
|