omg I never committed d24p2

20/graphviz.dot

@@ -0,0 +1,58 @@
+hb -> mj
+mx -> mt, NANDxz
+xh -> qc
+tg -> cq
+kp -> NANDxz, nj
+mj -> NANDjj, lv
+cq -> jm
+mt -> sj, NANDxz
+NANDjj -> hb, lz, NANDrk, xv, vj, vh, lv
+rm -> NANDbz, xq
+hx -> NANDbz
+xv -> lz
+xx -> kp, NANDxz
+pt -> vx
+NANDxz -> bq, gr, sj, rv, NANDzf
+vx -> NANDgf, cv
+xb -> NANDxz, bq
+xk -> NANDgf, rd
+lv -> zk
+NANDrk -> NANDgh
+kn -> NANDgf, tz
+NANDgh -> rx
+sj -> vp
+jm -> vm, NANDbz
+rr -> rv, NANDxz
+tz -> rz
+gg -> kn
+NANDcd -> NANDgh
+qc -> kh, NANDbz
+kb -> NANDgf
+vp -> NANDxz, xx
+fb -> NANDbz, tg
+rd -> cp
+qn -> vh, NANDjj
+xr -> NANDjj
+tp -> rm, NANDbz
+cp -> gg
+NANDbz -> NANDqx, cq, xh, fb, tg
+qq -> pt, NANDgf
+xq -> NANDbz, hx
+gx -> NANDjj, qv
+bq -> rr
+cv -> NANDgf, kb
+zk -> NANDjj, xv
+NANDzf -> NANDgh
+NANDqx -> NANDgh
+vh -> gx
+qv -> xr, NANDjj
+lz -> qn
+broadcaster -> fb, xk, gr, vj
+nj -> NANDxz
+gr -> NANDxz, xb
+kh -> tp, NANDbz
+vm -> NANDbz, xh
+rz -> qq, NANDgf
+NANDgf -> tz, NANDcd, rd, xk, pt, cp, gg
+rv -> mx
+vj -> hb, NANDjj

20/input.txt

@@ -0,0 +1,58 @@
+%hb -> mj
+%mx -> mt, xz
+%xh -> qc
+%tg -> cq
+%kp -> xz, nj
+%mj -> jj, lv
+%cq -> jm
+%mt -> sj, xz
+&jj -> hb, lz, rk, xv, vj, vh, lv
+%rm -> bz, xq
+%hx -> bz
+%xv -> lz
+%xx -> kp, xz
+%pt -> vx
+&xz -> bq, gr, sj, rv, zf
+%vx -> gf, cv
+%xb -> xz, bq
+%xk -> gf, rd
+%lv -> zk
+&rk -> gh
+%kn -> gf, tz
+&gh -> rx
+%sj -> vp
+%jm -> vm, bz
+%rr -> rv, xz
+%tz -> rz
+%gg -> kn
+&cd -> gh
+%qc -> kh, bz
+%kb -> gf
+%vp -> xz, xx
+%fb -> bz, tg
+%rd -> cp
+%qn -> vh, jj
+%xr -> jj
+%tp -> rm, bz
+%cp -> gg
+&bz -> qx, cq, xh, fb, tg
+%qq -> pt, gf
+%xq -> bz, hx
+%gx -> jj, qv
+%bq -> rr
+%cv -> gf, kb
+%zk -> jj, xv
+&zf -> gh
+&qx -> gh
+%vh -> gx
+%qv -> xr, jj
+%lz -> qn
+broadcaster -> fb, xk, gr, vj
+%nj -> xz
+%gr -> xz, xb
+%kh -> tp, bz
+%vm -> bz, xh
+%rz -> qq, gf
+&gf -> tz, cd, rd, xk, pt, cp, gg
+%rv -> mx
+%vj -> hb, jj

20/part1.pl

@@ -0,0 +1,82 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Circuit),
+    run1000(Circuit, Answer),
+    write(Answer), nl.
+
+% part1
+run1000(Circuit, Answer) :-
+    length(Range, 1000),
+    foldl(
+        {Circuit}/[_, In-Lin-Hin, Out-Lout-Hout]>>(
+            run([button-l-broadcaster], In, Out, L-H),
+            Lout is L+Lin, Hout is H+Hin),
+        Range, Circuit-0-0, _-Lx-Hx),
+    Answer is Lx*Hx.
+    
+% code to run one circuit
+run([], Circuit, Circuit, 0-0).
+run([Src-Level-Target|Pulses], CircuitIn, CircuitOut, Ls-Hs) :-
+    (   member(Type-Target-State-Dests, CircuitIn)
+    ->  /*write([Src, Level, Target]), write(" -> "),
+        write([Type, Target, State, Dests]), write(" = "),*/
+        call(Type, Src, Level, State, NewState, Out),
+        send(Target, Out, Dests, AdditionalPulses),
+        % write(NewState-AdditionalPulses), nl,
+        select(Type-Target-State-Dests, CircuitIn,
+            Type-Target-NewState-Dests, Circuit1),
+        append(Pulses, AdditionalPulses, NewPulses),
+        run(NewPulses, Circuit1, CircuitOut, NextLs-NextHs)
+    ;   run(Pulses, CircuitIn, CircuitOut, NextLs-NextHs)
+    ),
+    call(Level, NextLs-NextHs, Ls-Hs).
+
+l(L1s-H1s, L2s-H1s) :- L2s is L1s + 1.
+h(L1s-H1s, L1s-H2s) :- H2s is H1s + 1.
+
+broadcaster(_, l, x, x, l).
+
+ff(_, h, State, State, none).
+ff(_, l, 0, 1, h).
+ff(_, l, 1, 0, l).
+
+nand(Src, Level, State, NewState, OutLevel) :-
+    select(Src-_, State, Src-Level, NewState),
+    (maplist([_-h]>>(true), NewState) ->  OutLevel = l; OutLevel = h).
+
+send(_, none, _, []).
+send(From, Level, Dests, Pulses) :-
+    \+ Level = none,
+    maplist({Level}/[Dest, From-Level-Dest]>>(true), Dests, Pulses).
+
+% input initialization
+prefill_nands([], Circuit, Circuit).
+prefill_nands([_-Src-_-Dests|Nodes], CircuitIn, CircuitOut) :-
+    convlist(
+        {CircuitIn}/[Dest, Dest]>>(member(nand-Dest-_-_, CircuitIn)),
+        Dests, NandDests),
+    foldl(fill_one_nand(Src), NandDests, CircuitIn, Circuit1),
+    prefill_nands(Nodes, Circuit1, CircuitOut).
+
+fill_one_nand(Src, Nand, CIn, COut) :-
+    select(nand-Nand-State-Dests, CIn, nand-Nand-[Src-l|State]-Dests, COut).
+
+% input parsing stuff below
+input(FileName, Circuit) :-
+    phrase_from_file(modules(EmptyCircuit), FileName),
+    prefill_nands(EmptyCircuit, EmptyCircuit, Circuit).
+
+modules([]) --> eos, !.
+modules([Module|Modules]) --> module(Module), "\n", modules(Modules).
+
+module(broadcaster-broadcaster-x-Dests) --> "broadcaster -> ", dests(Dests).
+module(ff-Name-0-Dests) --> "%", node(Name), " -> ", dests(Dests).
+module(nand-Name-[]-Dests) --> "&", node(Name), " -> ", dests(Dests).
+
+dests([Dest]) --> node(Dest).
+dests([Dest|Dests]) --> node(Dest), ", ", dests(Dests).
+
+node(Name) --> string_without(", \n", NameStr), {atom_codes(Name, NameStr)}.

20/part2.pl

@@ -0,0 +1,82 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+% This code was only used to confirm the theory. Don't run it. Look at part2.txt.
+run_until(Circuit, _, Node, State, N) :- member(_-Node-State-_, Circuit), write(N), nl, !.
+run_until(Circuit, Init, Node, State, N) :-
+    maplist(extract(Circuit), [xr, qv, gx, vh, qn, lz, xv, zk, lv, mj, hb, vj], S1),
+    maplist(extract(Circuit), [nj, kp, xx, vp, sj, mt, mx, rv, rr, bq, xb, gr], S2),
+    maplist(extract(Circuit), [hx, xq, rm, tp, kh, qc, xh, vm, jm, cq, tg, fb], S3),
+    maplist(extract(Circuit), [kb, cv, vx, pt, qq, rz, tz, kn, gg, cp, rd, xk], S4),
+    
+    write(N), write(": "),
+    string_codes(Str1, S1), string_codes(Str2, S2), string_codes(Str3, S3), string_codes(Str4, S4),
+    write(Str1), write(" "), write(Str2), write(" "), write(Str3), write(" "), write(Str4), nl,
+    run([Init], Circuit, CircuitNext),
+    NextN is N + 1,
+    run_until(CircuitNext, Init, Node, State, NextN).
+
+extract(Circuit, Cell, AsciiState) :-
+    member(_-Cell-StateX-_, Circuit),
+    AsciiState is StateX + 48.
+
+% code to run one circuit
+run([], Circuit, Circuit) :- !.
+run([Src-Level-Target|Pulses], CircuitIn, CircuitOut) :-
+    (   member(Type-Target-State-Dests, CircuitIn)
+    ->  /*write([Src, Level, Target]), write(" -> "),
+        write([Type, Target, State, Dests]), write(" = "),*/
+        call(Type, Src, Level, State, NewState, Out),
+        send(Target, Out, Dests, AdditionalPulses),
+        % write(NewState-AdditionalPulses), nl,
+        select(Type-Target-State-Dests, CircuitIn,
+            Type-Target-NewState-Dests, Circuit1),
+        append(Pulses, AdditionalPulses, NewPulses),
+        run(NewPulses, Circuit1, CircuitOut)
+    ;   run(Pulses, CircuitIn, CircuitOut)
+    ).
+
+broadcaster(_, l, x, x, l).
+
+ff(_, h, State, State, none).
+ff(_, l, 0, 1, h).
+ff(_, l, 1, 0, l).
+
+nand(Src, Level, State, NewState, OutLevel) :-
+    select(Src-_, State, Src-Level, NewState),
+    (maplist([_-h]>>(true), NewState) ->  OutLevel = l; OutLevel = h).
+
+send(_, none, _, []).
+send(From, Level, Dests, Pulses) :-
+    \+ Level = none,
+    maplist({Level}/[Dest, From-Level-Dest]>>(true), Dests, Pulses).
+
+% input initialization
+prefill_nands([], Circuit, Circuit).
+prefill_nands([_-Src-_-Dests|Nodes], CircuitIn, CircuitOut) :-
+    convlist(
+        {CircuitIn}/[Dest, Dest]>>(member(nand-Dest-_-_, CircuitIn)),
+        Dests, NandDests),
+    foldl(fill_one_nand(Src), NandDests, CircuitIn, Circuit1),
+    prefill_nands(Nodes, Circuit1, CircuitOut).
+
+fill_one_nand(Src, Nand, CIn, COut) :-
+    select(nand-Nand-State-Dests, CIn, nand-Nand-[Src-l|State]-Dests, COut).
+
+% input parsing stuff below
+input(FileName, Circuit) :-
+    phrase_from_file(modules(EmptyCircuit), FileName),
+    prefill_nands(EmptyCircuit, EmptyCircuit, Circuit).
+
+modules([]) --> eos, !.
+modules([Module|Modules]) --> module(Module), "\n", modules(Modules).
+
+module(broadcaster-broadcaster-x-Dests) --> "broadcaster -> ", dests(Dests).
+module(ff-Name-0-Dests) --> "%", node(Name), " -> ", dests(Dests).
+module(nand-Name-[]-Dests) --> "&", node(Name), " -> ", dests(Dests).
+
+dests([Dest]) --> node(Dest).
+dests([Dest|Dests]) --> node(Dest), ", ", dests(Dests).
+
+node(Name) --> string_without(", \n", NameStr), {atom_codes(Name, NameStr)}.

20/part2.txt

@@ -0,0 +1,16 @@
+gh <- [qx, zf, cd, rk]
+
+Each of the 4 wings is a 12-bit counter, with custom resets at...
+
+xr, qv, gx, vh, qn, lz, xv, zk, lv, mj, hb, vj (jj) <- (111010010101) vj, qv, zk, gx, xr, qn, mj 
+nj, kp, xx, vp, sj, mt, mx, rv, rr, bq, xb, gr (xz) <- (111101101011) gr, nj, vp, rr, xb, xx, mt, kp, mx
+hx, xq, rm, tp, kh, qc, xh, vm, jm, cq, tg, fb (bz) <- (111111011001) vm, kh, xq, tp, fb, qc, jm, hx, rm
+kb, cv, vx, pt, qq, rz, tz, kn, gg, cp, rd, xk (gf) <- (111011010001) rz, cv, qq, kb, kn, xk, vx
+
+111010010101 = 3733 
+111101101011 = 3947 
+111111011001 = 4057 
+111011010001 = 3793
+
+All 4 are primes.
+LCD = 226732077152351

20/test.txt

@@ -0,0 +1,5 @@
+broadcaster -> a, b, c
+%a -> b
+%b -> c
+%c -> inv
+&inv -> a

20/test2.txt

@@ -0,0 +1,5 @@
+broadcaster -> a
+%a -> inv, con
+&inv -> b
+%b -> con
+&con -> output

21/input.txt

@@ -0,0 +1,131 @@
+...................................................................................................................................
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+..#.#..........#..........#.........#..#...#..........#.....#....................#.#..#.......#...........#............#...........
+.......#.....#...........##.........#.....#..........#....#..#......#...........#...##....#......................#....#.......#....
+..##......#...##.............................##..........#....#..............#..........#..............##..#....##.#........##.....
+....#......#....#.#..................#..........#....#.#..##.#.##........#.............................#...............#.......#.#.
+.............#..#......#.................#.#..#....####........#......#......#....#.#.....................#.#.#.#..#...............
+.##......#........##........#.............#.#.###.....#.............#.......#..##....#...#....................##..###.......#......
+....#.#......##.#.......#......#......................#.......#.........#..#...........#................#.........#..#...#....#....
+..........#....#..#...........#.................#...#..#.....................#.#........##.......#.#....#..#................##...#.
+......#....#.......#.......#..#...........#......#............#......#................#..........#...#.......##...#....#.#.........
+...#..##...##....#..#.......#....#.................#.#.....#....#........#..#.....####.#...........#..#............#...#..##.....#.
+..#......#...................#...............................#............#.....##.............#..#...#..##.#......#...............
+....#.........#.........#..............................#...#....#..#.#..............#...............#..##.........#.......#....#...
+.....#.........#....#.............#............................#.................##............#...#......#..........#.....#.....#.
+...#.#....#.......##...#....#............................##.#...#.......#...##...................#..........#.#....................
+...........#..#.###.....##...#.........#...........#..#.#.........#.#.#.......#.................#....#............###.........#..#.
+.##..........#..#......#.....##.##.#...##.........#.................#....#.#.....#.................#.....#...#....#.....###..#.#...
+......#.#..##.#.......#...#..#........................#..#..........#.#....#..##........#...#.#.............#.#....................
+.......#.#.............#..#.........................#.##..........##......................#...##.........#....#..........#..###....
+...............#..#...#.........#.........#.................#.#......#....................#.........#.......................#.#....
+.....#.................#.#...............##............................####...................##....#......#.#....##..#..#.......#.
+....#..#.......#.#...#.......................##.........#..#.......#.#.#............#...........#.###............#......#...##.....
+..#.#..........#..#.......#...#.........#....#.........#....#...#.......#.#..........##..##........................#..........##...
+....#...##......##......#.......#....###..............................#.##........................#......##.......#............#...
+...........#......#.#......#.............................#..........#...............#......##...............#.#........###.......#.
+..............#......#.....#.........#.....##....#..................#..##.......#.........##.#..##..................#....#.........
+....#...#...##.......###.......#....#...........#.#.............#...#.............#.#...#.#..................#..#.........#........
+................#.........#....#....#.##.....#...###..........#.......#...........#..#....#.............#....................##....
+.......................##..............#...#.#....##.#............#.#........#......##....#.......#........#.#.......#....#..#..#..
+..#....#..#............#.#...................#.....................................#.......##.#............##..#........#..........
+.....#............#.......##.........##...#........#........................................#................#.......#..........#..
+......#.#.....#.......#............##......#.#..#....#.........................#...............#..#.......##....###......###.......
+..#...................#.#...#.....#.......#..................................#..#....#......#.#...#..#..#......#.#.#....#....#.....
+...#....#....#.....#.....#.............................#.##..............#.....#..#.........#...#.....#........#.......#......##...
+.....#.......#.....#...#..#....#................#.......................#..#...#........#..........#....#..#....................#..
+......#.............#.#...#.##.......#...#.....#.....#.#.#...............#.....##.#....#...............................#.#.....#...
+...................................................................................................................................

21/part1.pl

@@ -0,0 +1,47 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Map, Starting),
+    nsteps(Map, 64, [Starting], Ends), length(Ends, Answer),
+    write(Answer), nl.
+
+nsteps(Map, N, Starts, Reachables) :-
+    length(Range, N),
+    foldl({Map}/[_, SIn, SOut]>>(step(Map, SIn, SOut)), Range, Starts, Reachables).
+    
+step(Map, CurrentCells, NextCells) :-
+    maplist(neighbors(Map), CurrentCells, NeighborsOfCells),
+    foldl(
+        [Neighbors, SetIn, SetOut]>>(
+            list_to_ord_set(Neighbors, NeighborsSet),
+            ord_union(SetIn, NeighborsSet, SetOut)),
+        NeighborsOfCells, [], NextCells).
+    
+neighbors(Map, X-Y, Neighbors) :-
+    findall(X1-Y1, neighbor(Map, X-Y, X1-Y1), Neighbors).
+
+neighbor(Map, X-Y, X1-Y1) :-
+    (   X1 is X, Y1 is Y+1; X1 is X, Y1 is Y-1;
+        X1 is X+1, Y1 is Y; X1 is X-1, Y1 is Y  ),
+    nth0(X1, Map, Row), nth0(Y1, Row, '.').
+
+replace(I, List, E, NewList) :- nth0(I, List, _, R), nth0(I, NewList, E, R).
+        
+% input parsing stuff below
+input(FileName, Map, StartX-StartY) :-
+    phrase_from_file(lines(MapS), FileName),
+    nth0(StartX, MapS, Row), nth0(StartY, Row, s),
+    select(s, Row, '.', NewRow), replace(StartX, MapS, NewRow, Map).
+
+lines([]) --> eos, !.
+lines([Line|Lines]) --> line(Line), lines(Lines).
+
+line([]) --> "\n"; eos.
+line([s|Chars]) --> "S", line(Chars).
+line(['.'|Chars]) --> ".", line(Chars).
+line(['#'|Chars]) --> "#", line(Chars).
+
+% Debug stuff
+print(Map) :- maplist([X]>>(atomics_to_string(X, XStr), write(XStr), nl), Map).

21/test.txt

@@ -0,0 +1,11 @@
+...........
+.....###.#.
+.###.##..#.
+..#.#...#..
+....#.#....
+.##..S####.
+.##..#...#.
+.......##..
+.##.#.####.
+.##..##.##.
+...........

22/part1.pl

@@ -0,0 +1,100 @@
+:- 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

22/part2.pl

@@ -0,0 +1,112 @@
+:- 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, StackedBricks),
+    support_listing(StackedBricks, Supporters, SupportMap),
+    length(Bricks, Len), TopBrick is Len - 1,
+    findall(
+        Goners,
+        (   between(0, TopBrick, Brick),
+            remove(SupportMap, [Brick], Supporters, Goners)),
+        GonerCounts),
+    sum_list(GonerCounts, Answer),
+    write(Answer), nl.
+
+remove(_, [], _, -1).
+remove(SupportMap, [N|ToKills], Supporters, Goners) :-
+    SupportedByN = SupportMap.N,
+    foldl(decrement_supporter_count, SupportedByN, Supporters, NewSupporters),
+    convlist({NewSupporters}/[X, X]>>(is_goner(NewSupporters, X)),
+             SupportedByN, ToKillMore),
+    append(ToKills, ToKillMore, ToKillNext),
+    remove(SupportMap, ToKillNext, NewSupporters, NextGoners),
+    Goners is NextGoners + 1.
+
+is_goner(Supporters, M) :- Supporters.M =< 0.
+    
+decrement_supporter_count(M, Supporters, NewSupporters) :-
+    NewCount is Supporters.M - 1,
+    NewSupporters = Supporters.put(M, NewCount).
+    
+% 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

22/test.txt

@@ -0,0 +1,7 @@
+1,0,1~1,2,1
+0,0,2~2,0,2
+0,2,3~2,2,3
+0,0,4~0,2,4
+2,0,5~2,2,5
+0,1,6~2,1,6
+1,1,8~1,1,9

23/input.txt

@@ -0,0 +1,141 @@
+#.###########################################################################################################################################
+#...###...#...#...#...###.....#...#...#.................#...#.......#.......###.....#.......#...#.....#####...#...#.....#.....###.....#.....#
+###.###.#.#.#.#.#.#.#.###.###.#.#.#.#.#.###############.#.#.#.#####.#.#####.###.###.#.#####.#.#.#.###.#####.#.#.#.#.###.#.###.###.###.#.###.#
+#...#...#.#.#.#.#.#.#.#...#...#.#.#.#.#...........#.....#.#.#.#.....#...#...#...#...#...#...#.#.#.#...#.....#...#.#.#...#...#.#...#...#...#.#
+#.###.###.#.#.#.#.#.#.#.###.###.#.#.#.###########.#.#####.#.#.#.#######.#.###.###.#####.#.###.#.#.#.###.#########.#.#.#####.#.#.###.#####.#.#
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+###.#.#.###.#v#.#.#.#.###.#.#.#######.#.#.###.#.#.#####.#.#########.#.###.#.###.#####.#####.#.#.#.#.#########.#.###.#####.#.#.###.#.#.#####.#
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+###########################################################################################################################################.#

23/part1.pl

@@ -0,0 +1,51 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Map),
+    nth1(1, Map, Row1), nth1(StartY, Row1, '.'),
+    findall(N, route(Map, visited{}, 1-StartY, N), Ns),
+    max_list(Ns, Answer),
+    format('~w <- ~w', [Answer, Ns]), nl.
+
+route(Map, _, X-_, 0) :- length(Map, Height), X =:= Height.
+route(Map, Visiteds, X-Y, N) :-
+    Key is X*1000 + Y, NextVisiteds = Visiteds.put(Key, true),
+    neighbor(Map, X-Y, X1-Y1, Dist),
+    NeighborKey is X1*1000 + Y1, \+ _= Visiteds.get(NeighborKey),
+    route(Map, NextVisiteds, X1-Y1, N1),
+    N is N1 + Dist.
+
+neighbor(Map, X-Y, NextX-NextY, Dist) :-
+    (   X1 is X + 1, Y1 = Y;
+        X1 is X - 1, Y1 = Y;
+        X1 = X, Y1 is Y + 1;
+        X1 = X, Y1 is Y - 1
+    ),
+    nth1(X1, Map, Row1), nth1(Y1, Row1, Cell1),
+    (   Cell1 = '.' -> NextX = X1, NextY = Y1, Dist = 1
+    ;   Cell1 = '>' -> NextX = X1, NextY is Y1 + 1, Dist = 2
+    ;   Cell1 = 'v' -> NextX is X1 + 1, NextY = Y1, Dist = 2
+    ), 
+    ( NextX =\= X; NextY =\= Y ).
+
+% input parsing stuff below. Brick indexing is for debugging.
+input(FileName, Map) :- phrase_from_file(lines(Map), FileName).
+
+lines([]) --> eos, !.
+lines([Line|Lines]) --> line(Line), lines(Lines).
+
+line([]) --> ("\n"; eos), !.
+line([C|Chars]) --> [Ascii], line(Chars), {atom_codes(C, [Ascii])}.
+
+% debug
+print(Map) :-
+    findall(
+        X,
+        (   nth1(X, Map, Line),
+            format('~3d', [X]), write(" "),
+            atomic_list_concat(Line, Str), write(Str), nl
+        ),
+        _),
+    nl.

23/part2.pl

@@ -0,0 +1,90 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+:- op(700, xfx, is_key_of).
+
+main([FileName|_]) :-
+    input(FileName, Map, Start, End),
+    graph(Map, Start, End, Graph),
+    StartKey is_key_of Start, EndKey is_key_of End,
+    findall(Dist, walk(Graph, visited{}, StartKey, EndKey, Dist), Dists),
+    max_list(Dists, Answer),
+    write(Answer), nl.
+
+walk(_, _, Node, Node, 0).
+walk(Graph, Visited, Start, End, Dist) :-
+    member(Next-NextDist, Graph.get(Start)), \+ _ = Visited.get(Next),
+    NextVisited = Visited.put(Next, true),
+    walk(Graph, NextVisited, Next, End, RemainingDist),
+    Dist is NextDist + RemainingDist.
+    
+graph(Map, Start, End, Graph) :-
+    branch_points(Map, Branches), Nodes = [Start, End|Branches],
+    findall(
+        Key-Dists,
+        (   member(Node, Nodes),
+            dists_from(Map, Nodes, Node, Dists),
+            Key is_key_of Node),
+        GraphList),
+    dict_pairs(Graph, edge, GraphList).
+        
+branch_points(Map, Points) :- findall(Point, branch_point(Map, Point), Points).
+branch_point(Map, X-Y) :-
+    nth1(X, Map, Row), nth1(Y, Row, Cell), Cell = '.',
+    findall(X1-Y1, cell_neighbor(Map, 0-0, X-Y, X1-Y1), Neighbors),
+    length(Neighbors, N), N > 2.
+
+dists_from(Map, Nodes, N1, Dists) :-
+    findall(
+        Key-Dist, (
+            member(N2, Nodes), \+ N1 = N2,
+            nobranch_dist(Map, 0-0, N1, N2, Dist),
+            Key is_key_of N2),
+        Dists).
+
+is_key_of(Key, X-Y) :- Key is X*1000 + Y.
+    
+% nobranch_dist(X1-Y1, X2-Y2, Dist) :- true.
+nobranch_dist(_, _, X-Y, X-Y, 0).
+nobranch_dist(Map, FromX-FromY, X1-Y1, X2-Y2, Dist) :-
+    findall(Xn-Yn, cell_neighbor(Map, FromX-FromY, X1-Y1, Xn-Yn), Neighbors),
+    length(Neighbors, NeighborCount),
+    \+ (NeighborCount =\= 1, FromX =\= 0),  % on a route or at beginning
+    member(Neighbor, Neighbors),
+    nobranch_dist(Map, X1-Y1, Neighbor, X2-Y2, NextDist),
+    Dist is NextDist + 1.
+    
+% cell_neighbor finds an adjacent neighbor
+cell_neighbor(Map, FromX-FromY, X-Y, X1-Y1) :-
+    (   X1 is X + 1, Y1 = Y;
+        X1 is X - 1, Y1 = Y;
+        X1 = X, Y1 is Y + 1;
+        X1 = X, Y1 is Y - 1
+    ),
+    nth1(X1, Map, Row1), nth1(Y1, Row1, '.'),
+    \+ (X1 = FromX, Y1 = FromY).
+
+% input parsing stuff below. Brick indexing is for debugging.
+input(FileName, Map, 1-StartY, EndX-EndY) :-
+    phrase_from_file(lines(Map), FileName),
+    length(Map, EndX),
+    nth1(1, Map, StartRow), nth1(StartY, StartRow, '.'),
+    nth1(EndX, Map, EndRow), nth1(EndY, EndRow, '.').
+
+lines([]) --> eos, !.
+lines([Line|Lines]) --> line(Line), lines(Lines).
+
+line([]) --> ("\n"; eos), !.
+line(['#'|Chars]) --> "#", line(Chars).
+line(['.'|Chars]) --> ("."; ">"; "v"), line(Chars).
+
+% debug
+print(Map) :-
+    findall(
+        X,
+        (   nth1(X, Map, Line),
+            format('~3d', [X]), write(" "),
+            atomic_list_concat(Line, Str), write(Str), nl
+        ),
+        _),
+    nl.

23/test.txt

@@ -0,0 +1,23 @@
+#.#####################
+#.......#########...###
+#######.#########.#.###
+###.....#.>.>.###.#.###
+###v#####.#v#.###.#.###
+###.>...#.#.#.....#...#
+###v###.#.#.#########.#
+###...#.#.#.......#...#
+#####.#.#.#######.#.###
+#.....#.#.#.......#...#
+#.#####.#.#.#########v#
+#.#...#...#...###...>.#
+#.#.#v#######v###.###v#
+#...#.>.#...>.>.#.###.#
+#####v#.#.###v#.#.###.#
+#.....#...#...#.#.#...#
+#.#########.###.#.#.###
+#...###...#...#...#.###
+###.###.#.###v#####v###
+#...#...#.#.>.>.#.>.###
+#.###.###.#.###.#.#v###
+#.....###...###...#...#
+#####################.#

24/input.txt

@@ -0,0 +1,300 @@
+320870677764563, 335750934489987, 282502845957937 @ -40, -24, 10
+219235623600942, 408022798608755, 245679379684914 @ 127, -45, 66
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+177207555863420, 203871290203365, 289811933188528 @ -74, -84, -479
+190420105339073, 167303615894628, 216289073804446 @ 110, 219, 117
+266399617296604, 299362499051479, 325520686693096 @ -20, -33, -95
+481245676627650, 436807969705569, 314107082127180 @ -202, -116, -19
+401026926420116, 374922905725809, 350888777956543 @ -101, -38, -62
+256839644239620, 270114181543499, 257354063805598 @ 26, 47, 40
+412259775717406, 242736865487561, 424824610687152 @ -86, 128, -130
+66312913166752, 101998933996761, 60120199695721 @ 283, 274, 250
+506958247823068, 361333863900433, 280005516982136 @ -152, 18, 33
+298773017825360, 317212540408089, 312439900056100 @ 12, 22, -21
+220796554287875, 214622218414014, 268263970137525 @ -96, 37, -66
+189208611146850, 404126141855649, 112689238573260 @ 52, -656, 531
+234488363250114, 231264618839649, 204011914548812 @ 65, 112, 126
+283632869172150, 177048553588739, 391393075492010 @ -121, 197, -300
+502765928206235, 353125800556389, 304677713378740 @ -156, 22, 7
+137557454494001, 97473160546677, 94622893468780 @ 242, 470, 559
+254064108665930, 262174096766589, 289808760599414 @ 21, 52, -18
+182103896038108, 247435234271202, 351160194849282 @ -25, -299, -735
+249420082303430, 42226989901413, 97645217504204 @ 36, 421, 303
+284785302989480, 255729203245377, 252686569800496 @ -94, 26, 37
+233601301711332, 322776864011749, 366444377930614 @ 70, -28, -128
+155098520524958, 244934576541158, 226621458469431 @ 165, -241, 122
+146746875809578, 160303698184733, 228748383224514 @ 205, 224, 86
+326652196225864, 355170482041167, 311279979189430 @ -38, -41, -26
+277275275212730, 369459942642369, 282937479061000 @ 59, -14, 24
+295687269134249, 340949989963329, 238600197559195 @ 60, 42, 74
+279992481783853, 333185439596083, 324914479814764 @ 64, 36, -17
+241428276856914, 266598398788449, 362846190951676 @ -40, -38, -260
+259307794913743, 295678437418021, 269285719406143 @ 8, -10, 16
+240223936950226, 473763454154241, 220230835580308 @ 77, -206, 97
+318558193417106, 334499570437515, 230529981435367 @ 25, 36, 82
+275715901048290, 73132232580276, 217625216713160 @ 41, 331, 99
+193044713426762, 394683970973463, 372101396303146 @ 145, -80, -99
+145897314675055, 223949571890769, 176036980234010 @ 232, -230, 585
+161440895273330, 237913221256553, 291149659043788 @ 171, 45, -65
+264388423069872, 379242075888111, 338900807126713 @ -5, -164, -110
+335398015038338, 259239092404812, 434897503751132 @ 9, 115, -129
+236716202526674, 332397372379329, 276349416527020 @ 79, -18, 19
+322665826998882, 358742494848305, 303038334161388 @ -13, -25, -7
+428381456361421, 547609324289011, 198413346560546 @ -70, -160, 113
+157290994488974, 206478542217105, 303245653405090 @ 157, 26, -311
+395914211954640, 425947992394193, 312165656677126 @ -184, -190, -44
+244618900201418, 557301378477177, 207722519450068 @ -51, -810, 147
+279386951121298, 308300290814141, 289436636980500 @ -31, -36, -21
+306161107858370, 145704637204577, 363514529004748 @ -99, 258, -170
+157069989582566, 150135411048405, 169136269193176 @ 168, 309, 356
+149210988438152, 134368802376762, 209337851128249 @ 203, 605, 318
+332584662588854, 503022806009046, 148583395713307 @ -43, -235, 192
+470742777193259, 423305548535160, 228962588950855 @ -160, -77, 84
+250671602810546, 250908746265621, 243056875754412 @ -135, -50, 47
+531229816428916, 231708023716351, 470967021948546 @ -196, 143, -168
+237893080628802, 139019131653901, 131107424449688 @ 73, 254, 227
+218711687951546, 159752359004265, 320741448667460 @ 78, 229, -76
+165313081944257, 184601129061069, 299424839638243 @ 168, 182, -58
+307210181456654, 421282787395425, 479731549148236 @ 37, -54, -177
+305412361284452, 343104362104491, 360276884155534 @ -56, -75, -130
+368644982396221, 368636169652378, 540142064185444 @ -22, 5, -233
+296336361357714, 453921261262757, 388278886187068 @ 53, -79, -77
+431597308261298, 363087620944641, 307225389042377 @ -231, -86, -34
+302152593338480, 335110106105791, 293583504813410 @ 36, 29, 14

24/part1.pl

@@ -0,0 +1,35 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Hails),
+    maplist(xyline, Hails, Lines),
+    findall(
+        [N1, N2, X, Y], (
+            member(N1-L1-X1assert, Lines), member(N2-L2-X2assert, Lines), N1 < N2,
+            intersect(L1, L2, X-Y), call(X1assert, X), call(X2assert, X),
+            X >= 200000000000000, X =< 400000000000000,
+            Y >= 200000000000000, Y =< 400000000000000),
+        Intersects),
+    length(Intersects, Answer),
+    write(Answer), nl.
+
+intersect(A1-B1-C1, A2-B2-C2, X-Y) :-
+    Det is A1*B2 - A2*B1, Det =\= 0,
+    X is (B2*C1 - B1*C2) / Det,
+    Y is (-A2*C1 + A1*C2) / Det.
+    
+xyline(N-(X-Y-_-Dx-Dy-_), N-(A-B-C)-Xassert) :-
+    A = Dy, B is -Dx, C is X*Dy - Y*Dx,
+    ( Dx >= 0 -> Xassert = =<(X); Xassert = >=(X) ).
+
+% input parsing stuff below. Brick indexing is for debugging.
+% assumption: no same hail. There are parallels, but no same
+input(FileName, Hails) :- phrase_from_file(hails(0, Hails), FileName).
+
+hails(_, []) --> eos, !.
+hails(N, [N-(X-Y-Z-Dx-Dy-Dz)|Hails]) -->
+    blanks, number(X), ",", blanks, number(Y), ",", blanks, number(Z), " @",
+    blanks, number(Dx), ",", blanks, number(Dy), ",", blanks, number(Dz), "\n",
+    {NextN is N + 1}, hails(NextN, Hails).

24/part2.pl

@@ -0,0 +1,35 @@
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Hails),
+    maplist(xyline, Hails, Lines),
+    findall(
+        [N1, N2, X, Y], (
+            member(N1-L1-X1assert, Lines), member(N2-L2-X2assert, Lines), N1 < N2,
+            intersect(L1, L2, X-Y), call(X1assert, X), call(X2assert, X),
+            X >= 200000000000000, X =< 400000000000000,
+            Y >= 200000000000000, Y =< 400000000000000),
+        Intersects),
+    length(Intersects, Answer),
+    write(Answer), nl.
+
+intersect(A1-B1-C1, A2-B2-C2, X-Y) :-
+    Det is A1*B2 - A2*B1, Det =\= 0,
+    X is (B2*C1 - B1*C2) / Det,
+    Y is (-A2*C1 + A1*C2) / Det.
+    
+xyline(N-(X-Y-_-Dx-Dy-_), N-(A-B-C)-Xassert) :-
+    A = Dy, B is -Dx, C is X*Dy - Y*Dx,
+    ( Dx >= 0 -> Xassert = =<(X); Xassert = >=(X) ).
+
+% input parsing stuff below. Brick indexing is for debugging.
+% assumption: no same hail. There are parallels, but no same
+input(FileName, Hails) :- phrase_from_file(hails(0, Hails), FileName).
+
+hails(_, []) --> eos, !.
+hails(N, [N-(X-Y-Z-Dx-Dy-Dz)|Hails]) -->
+    blanks, number(X), ",", blanks, number(Y), ",", blanks, number(Z), " @",
+    blanks, number(Dx), ",", blanks, number(Dy), ",", blanks, number(Dz), "\n",
+    {NextN is N + 1}, hails(NextN, Hails).

24/test.txt

@@ -0,0 +1,27 @@
+19, 13, 30 @ -2,  1, -2
+18, 19, 22 @ -1, -1, -2
+20, 25, 34 @ -2, -2, -4
+12, 31, 28 @ -1, -2, -1
+20, 19, 15 @  1, -5, -3
+
+Using first 3 rays
+
+x + a*t1 = 19 - 2t1, y + b*t1 = 13 + t1, z + c*t1 = 30 - 2t1,
+x + a*t2 = 18 - t2, y + b*t2 = 19 - t2, z + c*t2 = 22 - 2t2,
+x + a*t3 = 20 - 2t3, y + b*t3 = 25 - 2t3, z + c*t3 = 34 - 4t3
+9 eqs, 9 unks, thus solution in 3 points.
+--> a = -3, b = 1, c = 2, t1 = 5, t2 = 3, t3 = 4, x = 24, y = 13, z = 10
+
+x+a*t1 == 320870677764563-40*t1, y+b*t1 == 335750934489987-24*t1, z+c*t1 == 282502845957937+10*t1,
+x+a*t2 == 219235623600942+127*t2, y+b*t2 == 408022798608755-45*t2, z+c*t2 == 245679379684914+66*t2,
+x+a*t3 == 171834827764229-122*t3, y+b*t3 == 225154401936948-521*t3, z+c*t3 == 232302441670972+95*t3
+
+sage: x, y, z, a, b, c, t1, t2, t3 = var('x, y, z, a, b, c, t1, t2, t3')
+sage: solve([
+....:     x+a*t1 == 320870677764563-40*t1, y+b*t1 == 335750934489987-24*t1, z+c*t1 == 282502845957937+10*t1,
+....:     x+a*t2 == 219235623600942+127*t2, y+b*t2 == 408022798608755-45*t2, z+c*t2 == 245679379684914+66*t2,
+....:     x+a*t3 == 171834827764229-122*t3, y+b*t3 == 225154401936948-521*t3, z+c*t3 == 232302441670972+95*t3],
+....:   x,y,z,a,b,c,t1,t2,t3)
+[[x == 149412455352770, y == 174964385672289, z == 233413147425100, a == 201, b == 202, c == 79, t1 == 711444906273, t2 == 943556327678, t3 == 69419109633]]
+sage: 149412455352770+174964385672289+233413147425100
+557789988450159

25/part1.pl

@@ -0,0 +1,91 @@
+% This needs more stack. Try --stack_limit=4G
+:- use_module(library(pio)).
+:- use_module(library(dcg/basics)).
+:- initialization(main, main).
+
+main([FileName|_]) :-
+    input(FileName, Conns),
+    dict_pairs(Conns, _, ConnsList),
+    length(ConnsList, NNodes),
+    findnsols(
+        1, PartitionSize, (
+            _ = Conns.StartNode,
+            iterate(StartNode, EndNode, Conns, _),
+            atom_length(EndNode, NodeSize3),
+            PartitionSize is NodeSize3 / 3),
+        [Side1]),
+    Side2 is NNodes - Side1,
+    Answer is Side1*Side2,
+    write(Answer), nl.
+
+iterate(Node, Node, Graph, Graph) :- length(Graph.Node, 3), !.
+iterate(Node0, Node, Graph0, Graph) :-
+    countall(Graph0.Node0, NeighborCounts),
+    NeighborCounts = [_-Max|_],
+    member(Neighbor-Max, NeighborCounts),
+    combine(Node0, Neighbor, Node1, Graph0, Graph1),
+    iterate(Node1, Node, Graph1, Graph).
+    
+% combine 2 nodes into one, keep all outbound connections
+combine(Node1, Node2, Node12, Graph0, Graph) :-
+    % delete N1 -> N2's and N2 -> N1's
+    del_dict(Node1, Graph0, OldN1Outs, Graph1),
+    del_dict(Node2, Graph1, OldN2Outs, Graph2),
+    remove_all(Node2, OldN1Outs, N1Outs),
+    remove_all(Node1, OldN2Outs, N2Outs),
+    % replace N1 -> X and N2 -> Y with N12 -> [X|Y]
+    atom_concat(Node1, Node2, Node12),
+    append(N1Outs, N2Outs, N12Outs),
+    Graph3 = Graph2.put(Node12, N12Outs),
+    % replace X -> N1 or X -> N2 with X -> N12 (twice if needed)
+    foldl(replace_outbound_node(Node1, Node12), N1Outs, Graph3, Graph4),
+    foldl(replace_outbound_node(Node2, Node12), N2Outs, Graph4, Graph).
+
+replace_outbound_node(Node1, Node2, Node, Graph0, Graph) :-
+    replace_all(Node1, Graph0.Node, Node2, NewList),
+    Graph = Graph0.put(Node, NewList).
+
+% List has all items in List but with all ItemOut instances replaced with ItemIn
+replace_all(_, [], _, []).
+replace_all(ItemOut, [ItemOut|List0], ItemIn, [ItemIn|List]) :-
+    replace_all(ItemOut, List0, ItemIn, List).
+replace_all(ItemOut, [X|List0], ItemIn, [X|List]) :-
+    \+ X = ItemOut,
+    replace_all(ItemOut, List0, ItemIn, List).
+
+remove_all(_, [], []).
+remove_all(X, [X|List], ListOut) :- remove_all(X, List, ListOut).
+remove_all(X, [Y|List], [Y|ListOut]) :- \+ X = Y, remove_all(X, List, ListOut).
+    
+% countall means Counts is pairs of Item-Count where Item in List, sorted >
+countall(List, Counts) :-
+    foldl(increment, List, count{}, CountsMap),
+    dict_pairs(CountsMap, _, CountsList),
+    sort(2, @>=, CountsList, Counts).
+
+increment(X, Ns0, Ns) :- Next is Ns0.get(X, 0) + 1, Ns = Ns0.put(X, Next).
+    
+% input parsing stuff below.
+input(FileName, Conns) :-
+    phrase_from_file(conns(ConnsList), FileName),
+    to_bidi_graph(ConnsList, Conns).
+
+conns([]) --> eos, !.
+conns([From-Tos|Conns]) --> node(From), ": ", tos(Tos), conns(Conns).
+tos([To]) --> node(To), "\n".
+tos([To|Tos]) --> node(To), " ", tos(Tos).
+node(Node) --> string_without(": \n", NodeStr), {atom_codes(Node, NodeStr)}.
+
+to_bidi_graph(ConnsList, BidiConnsGraph) :-
+    dict_pairs(Graph0, conn, ConnsList),
+    foldl(add_reverse_conns_for, ConnsList, Graph0, BidiConnsGraph).
+
+add_reverse_conns_for(Node-Outbounds, Conns0, Conns1) :-
+    foldl(add_conn(Node), Outbounds, Conns0, Conns1).
+
+add_conn(ToNode, FromNode, Conns0, Conns1) :-
+    Current = Conns0.get(FromNode, []),
+    Conns1 = Conns0.put(FromNode, [ToNode|Current]).
+
+% debug
+print(Graph) :- dict_pairs(Graph, _, Lines), maplist(format('~w~n'), Lines).

25/test.txt

@@ -0,0 +1,13 @@
+jqt: rhn xhk nvd
+rsh: frs pzl lsr
+xhk: hfx
+cmg: qnr nvd lhk bvb
+rhn: xhk bvb hfx
+bvb: xhk hfx
+pzl: lsr hfx nvd
+qnr: nvd
+ntq: jqt hfx bvb xhk
+nvd: lhk
+lsr: lhk
+rzs: qnr cmg lsr rsh
+frs: qnr lhk lsr