gistfile1.txt

%% @type sspec() = {dist(), board()}.
%% @type dist()  = integer().
%% @type field() = [info()].
%% @type info()  = s | w | integer().
%% @type board() = [[field()]].

%% @type ssol() = [[integer()]].

%% @spec khf2:n_away(SSpec::sspec(), SSol::ssol()) -> B::bool().

%% B igaz, ha az SSol részlegesen kitöltött érték-mátrix teljesíti az SSpec
%% Sudoku-feladványban szereplő távolságinfók által támasztott feltételeket.

-module(khf2).
-author('najibg96@gmail.com').
-vsn('2017-10-17').
-export([n_away/2]).

n_away({_N, [[[]]]}, _) ->
	true;

n_away({N, RULEM}, VALUEM) when length(RULEM) =:= length(VALUEM)->
	down_n_away_check(N, w, RULEM, VALUEM) andalso down_n_away_check(N, s, transpose(RULEM), transpose(VALUEM)).

down_n_away_check(N, D, [RMH | RMT], [VMH | VMT]) ->
	right_n_away_check(N, D, RMH, VMH) andalso down_n_away_check(N, D, RMT, VMT).

right_n_away_check(_N, _D, [_RULE], [_NUM]) ->
	true;

right_n_away_check(N, D, [ _ , RULE | RULESTAIL], [ PREVNUM, NUM | NUMSTAIL ] ) ->
	rule_check(N, D, PREVNUM, RULE, NUM) andalso right_n_away_check(N, D, [RULE]++RULESTAIL, [NUM]++NUMSTAIL).

rule_check(N, w, PREVNUM,  [w | _], NUM) ->
	disance_check(N, PREVNUM, NUM);

rule_check(N, w, PREVNUM, [_, w | _], NUM) ->
	disance_check(N, PREVNUM, NUM);

rule_check(N, w, PREVNUM, [s | _ ], NUM) ->
	not disance_check(N,PREVNUM,NUM);

rule_check(N, w, PREVNUM, [], NUM) ->
	not disance_check(N,PREVNUM,NUM);

rule_check(N, s, PREVNUM, [s | _ ], NUM) ->
	disance_check(N, PREVNUM, NUM);

rule_check(N, s, PREVNUM,  [w | _], NUM) ->
	not disance_check(N,PREVNUM,NUM);

rule_check(N, s, PREVNUM, [_, w | _], NUM) ->
	not disance_check(N,PREVNUM,NUM);

rule_check(N, s, PREVNUM, [], NUM) ->
	not disance_check(N,PREVNUM,NUM).

disance_check(N, PREVNUM, NUM) ->
	N =:= abs(PREVNUM-NUM).

transpose([[]|_]) -> [];
transpose(M) ->
  [lists:map(fun hd/1, M) | transpose(lists:map(fun tl/1, M))].