Merge pull request #2875 from adamcrussell/challenge-088

Prolog solution to part 2.

1 files changed, 65 insertions, 0 deletions

diff --git a/challenge-088/adam-russell/prolog/ch-2.p b/challenge-088/adam-russell/prolog/ch-2.p
new file mode 100644
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+++ b/challenge-088/adam-russell/prolog/ch-2.p
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+/*
+    You are given m x n matrix of positive integers.
+    Write a script to print spiral matrix as a list.
+*/
+write_remove_top(Matrix, UpdatedMatrix):-
+    nth0(0, Matrix, Top),
+    atomic_list_concat(Top, ",", TopString),
+    write(TopString),
+    nth0(0, Matrix, _, UpdatedMatrix).
+
+write_remove_last([], UpdatedMatrix, UpdatedMatrix).
+write_remove_last([H|T], RemainderAccum, UpdatedMatrix):-
+    length(H, L),
+    Last is L - 1,
+    nth0(Last, H, Right),
+    write(Right),
+    write(","),
+    nth0(Last, H, _, UpdatedRow),
+    write_remove_last(T, [UpdatedRow|RemainderAccum], UpdatedMatrix).
+
+write_remove_right(Matrix, UpdatedMatrix):-
+    write_remove_last(Matrix, [], UpdatedMatrix).
+
+write_remove_first([], UpdatedMatrix, UpdatedMatrix).
+write_remove_first([H|T], RemainderAccum, UpdatedMatrix):-
+    nth0(0, H, Left),
+    write(Left),
+    write(","),
+    nth0(0, H, _, UpdatedRow),
+    write_remove_first(T, [UpdatedRow|RemainderAccum], UpdatedMatrix).
+
+write_remove_left(Matrix, UpdatedMatrix):-
+    write_remove_first(Matrix, [], UpdatedMatrix).
+
+write_remove_bottom(Matrix, UpdatedMatrix):-
+    length(Matrix, L),
+    Last is L - 1,
+    nth0(Last, Matrix, Bottom),
+    reverse(Bottom, ReverseBottom),
+    atomic_list_concat(ReverseBottom, ",", BottomString),
+    write(BottomString),
+    nth0(Last, Matrix, _, UpdatedMatrix).
+    
+    
+spiral(Matrix):-
+    spiral(Matrix, _).
+spiral([], _).    
+spiral(Matrix, UpdatedMatrix):-
+    write_remove_top(Matrix, UpdatedMatrix),
+    write(","),
+    write_remove_right(UpdatedMatrix, RightRemainder),
+    reverse(RightRemainder, RemainderRight),
+    write_remove_bottom(RemainderRight, BottomRemainder), 
+    write(","),
+    write_remove_left(BottomRemainder, LeftRemainder), 
+    spiral(LeftRemainder, []).
+spiral(_, []):-
+    write("\b").
+    
+main:-
+    spiral([
+        [ 1, 2, 3 ],
+        [ 4, 5, 6 ],
+        [ 7, 8, 9 ]
+    ]), halt.