Anonymous user
Permutations by swapping: Difference between revisions
Updated both D entries
No edit summary |
(Updated both D entries) |
||
Line 238:
=={{header|D}}==
===Iterative Version===
This isn't a Range yet.
{{trans|Python}}
<lang d>import std.algorithm, std.array, std.typecons, std.range;
Line 246:
alias TResult = Tuple!(int[], int);
int opApply(in int delegate(in ref TResult) nothrow dg) nothrow {
int result;
Line 260:
goto END;
while (p.
// Failed to use std.algorithm here, too much complex.
auto largest = Int2(-100, -100);
int i1 = -1;
foreach (immutable i, immutable pi; p)
if (pi[1])
if (pi[0] > largest[0]) {
i1 = i;
largest = pi;
}
}▼
immutable n1 = largest[0],
d1 = largest[1];
Line 364 ⟶ 362:
===Recursive Version===
{{trans|Python}}
<lang d>import std.algorithm, std.array, std.typecons, std.range;
auto sPermutations(in
static immutable(int[])[]
if (items <= 0)
return [[]];
typeof(return) r;
foreach (immutable i, immutable item;
//r.put((i % 2 ? iota(cast(int)item.length, -1, -1) :
// iota(item.length + 1))
// .map!(i => item[0 .. i] ~ (items - 1) ~ item[i .. $]));
immutable f = (in
item[0 .. i] ~ (items - 1) ~ item[i .. $];
r ~= (i % 2) ?
//iota(cast(int)item.length, -1, -1).map!f.array :
iota(item.length + 1).retro.map!f.array :
iota(item.length + 1).map!f.array;
}
Line 385 ⟶ 384:
}
return
}
void main() {
import std.stdio;
foreach (immutable n; [2, 3, 4]) {
writefln("
foreach (
writefln("
}
}</lang>
{{out}}
<pre>Permutations and sign of 2 items:
[1, 0] Sign: 1
[0, 1] Sign: -1
Permutations and sign of 3 items:
[2, 1, 0] Sign: 1
[1, 2, 0] Sign: -1
[1, 0, 2] Sign: 1
[0, 1, 2] Sign: -1
[0, 2, 1] Sign: 1
[2, 0, 1] Sign: -1
Permutations and sign of 4 items:
[3, 2, 1, 0] Sign: 1
[2, 3, 1, 0] Sign: -1
[2, 1, 3, 0] Sign: 1
[2, 1, 0, 3] Sign: -1
[1, 2, 0, 3] Sign: 1
[1, 2, 3, 0] Sign: -1
[1, 3, 2, 0] Sign: 1
[3, 1, 2, 0] Sign: -1
[3, 1, 0, 2] Sign: 1
[1, 3, 0, 2] Sign: -1
[1, 0, 3, 2] Sign: 1
[1, 0, 2, 3] Sign: -1
[0, 1, 2, 3] Sign: 1
[0, 1, 3, 2] Sign: -1
[0, 3, 1, 2] Sign: 1
[3, 0, 1, 2] Sign: -1
[3, 0, 2, 1] Sign: 1
[0, 3, 2, 1] Sign: -1
[0, 2, 3, 1] Sign: 1
[0, 2, 1, 3] Sign: -1
[2, 0, 1, 3] Sign: 1
[2, 0, 3, 1] Sign: -1
[2, 3, 0, 1] Sign: 1
[3, 2, 0, 1] Sign: -1
</pre>
=={{header|Go}}==
| |||