new files

Task/Balanced-ternary/Erlang/balanced-ternary-1.erl

@@ -0,0 +1,89 @@
+-module(ternary).
+-compile(export_all).
+
+test() ->
+    AS = "+-0++0+", AT = from_string(AS), A = from_ternary(AT),
+    B = -436, BT = to_ternary(B), BS = to_string(BT),
+    CS = "+-++-", CT = from_string(CS), C = from_ternary(CT),
+    RT = mul(AT,sub(BT,CT)),
+    R = from_ternary(RT),
+    RS = to_string(RT),
+    io:fwrite("A = ~s -> ~b~n",[AS, A]),
+    io:fwrite("B = ~s -> ~b~n",[BS, B]),
+    io:fwrite("C = ~s -> ~b~n",[CS, C]),
+    io:fwrite("A x (B - C) = ~s -> ~b~n", [RS, R]).
+
+to_string(T) -> [to_char(X) || X <- T].
+
+from_string(S) -> [from_char(X) || X <- S].
+
+to_char(-1) -> $-;
+to_char(0) -> $0;
+to_char(1) -> $+.
+
+from_char($-) -> -1;
+from_char($0) -> 0;
+from_char($+) -> 1.
+
+to_ternary(N) when N > 0 ->
+    to_ternary(N,[]);
+to_ternary(N) ->
+    neg(to_ternary(-N)).
+
+to_ternary(0,Acc) ->
+    Acc;
+to_ternary(N,Acc) when N rem 3 == 0 ->
+    to_ternary(N div 3, [0|Acc]);
+to_ternary(N,Acc) when N rem 3 == 1 ->
+    to_ternary(N div 3, [1|Acc]);
+to_ternary(N,Acc) ->
+    to_ternary((N+1) div 3, [-1|Acc]).
+
+from_ternary(T) -> from_ternary(T,0).
+
+from_ternary([],Acc) ->
+    Acc;
+from_ternary([H|T],Acc) ->
+    from_ternary(T,Acc*3 + H).
+
+mul(A,B) -> mul(B,A,[]).
+
+mul(_,[],Acc) ->
+    Acc;
+mul(B,[A|As],Acc) ->
+    BP = case A of
+             -1 -> neg(B);
+             0 ->  [0];
+             1 ->  B
+         end,
+    A1 = Acc++[0],
+    A2=add(BP,A1),
+    mul(B,As,A2).
+
+
+neg(T) -> [ -H || H <- T].
+
+sub(A,B) -> add(A,neg(B)).
+
+add(A,B) when length(A) < length(B) ->
+    add(lists:duplicate(length(B)-length(A),0)++A,B);
+add(A,B) when length(A) > length(B) ->
+   add(B,A);
+add(A,B) ->
+    add(lists:reverse(A),lists:reverse(B),0,[]).
+
+add([],[],0,Acc) ->
+    Acc;
+add([],[],C,Acc) ->
+    [C|Acc];
+add([A|As],[B|Bs],C,Acc) ->
+    [C1,D] = add_util(A+B+C),
+    add(As,Bs,C1,[D|Acc]).
+
+add_util(-3) -> [-1,0];
+add_util(-2) -> [-1,1];
+add_util(-1) -> [0,-1];
+add_util(3) -> [1,0];
+add_util(2) -> [1,-1];
+add_util(1) -> [0,1];
+add_util(0) -> [0,0].

Task/Balanced-ternary/Erlang/balanced-ternary-2.erl

@@ -0,0 +1,6 @@
+234> ternary:test().
+A = +-0++0+ -> 523
+B = -++-0-- -> -436
+C = +-++- -> 65
+A x (B - C) = 0----0+--0++0 -> -262023
+ok