Balanced ternary: Difference between revisions
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→{{header|Koka}}
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a * (b - c): -262023, ----0+--0++0</pre>
=={{header|Koka}}==
Based on the OCaml version
<syntaxhighlight lang="koka">
type btdigit
Pos
Zero
Neg
alias btern = list<btdigit>
fun to_string(n: btern): string
join(
n.reverse.map fn(d)
match d
Pos -> "+"
Zero -> "0"
Neg -> "-"
)
fun from_string(s: string): exn btern
var sl := Nil
s.foreach fn(c)
match c
'+' -> sl := Cons(Pos, sl)
'0' -> sl := Cons(Zero, sl)
'-' -> sl := Cons(Neg, sl)
_ -> throw("Invalid Character")
sl
fun to_int(n: btern): int
match n
Nil -> 0
Cons(Zero, Nil) -> 0
Cons(Pos, rst) -> 1+3*rst.to_int
Cons(Neg, rst) -> -1+3*rst.to_int
Cons(Zero, rst) -> 3*rst.to_int
fun from_int(n: int): <exn> btern
if n == 0 then [] else
match n % 3
0 -> Cons(Zero, from_int((n/3).unsafe-decreasing))
1 -> Cons(Pos, from_int(((n - 1)/3).unsafe-decreasing))
2 -> Cons(Neg, from_int(((n+1)/3).unsafe-decreasing))
_ -> throw("Impossible")
fun (+)(n1: btern, n2: btern): <exn,div> btern
match (n1, n2)
([], a) -> a
(a, []) -> a
(Cons(Pos, t1), Cons(Neg, t2)) ->
val sum = t1 + t2
if sum.is-nil then [] else Cons(Zero, sum)
(Cons(Neg, t1), Cons(Pos, t2)) ->
val sum = t1 + t2
if sum.is-nil then [] else Cons(Zero, sum)
(Cons(Zero, t1), Cons(Zero, t2)) ->
val sum = t1 + t2
if sum.is-nil then [] else Cons(Zero, sum)
(Cons(Pos, t1), Cons(Pos, t2)) -> Cons(Neg, t1 + t2 + [Pos])
(Cons(Neg, t1), Cons(Neg, t2)) -> Cons(Pos, t1 + t2 + [Neg])
(Cons(Zero, t1), Cons(h, t2)) -> Cons(h, t1 + t2)
(Cons(h, t1), Cons(Zero, t2)) -> Cons(h, t1 + t2)
_ -> throw("Impossible")
fun neg(n: btern)
n.map fn(d)
match d
Pos -> Neg
Zero -> Zero
Neg -> Pos
fun (-)(n1: btern, n2: btern): <exn,div> btern
n1 + neg(n2)
fun (*)(n1, n2)
match n2
[] -> []
[Pos] -> n1
[Neg] -> n1.neg
(Cons(Pos, t)) -> Cons(Zero, t*n1) + n1
(Cons(Neg, t)) -> Cons(Zero, t*n1) - n1
(Cons(Zero, t)) -> Cons(Zero, t*n1)
fun main()
val a = "+-0++0+".from_string
val b = (-436).from_int
val c = "+-++-".from_string
val d = a * (b - c)
println("a = " ++ a.to_int.show ++ "\nb = " ++ b.to_string ++ "\nc = " ++ c.to_int.show ++ "\na * (b - c) = " ++ d.to_string ++ " = " ++ d.to_int.show )
</syntaxhighlight>
{{out}}
<pre>
a = 523
b = -++-0--
c = 65
a * (b - c) = ----0+--0++0 = -262023
</pre>
=={{header|Kotlin}}==
This is based on the Java entry. However, I've added 'BigInteger' support as this is a current requirement of the task description even though it's not actually needed to process the test case:
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