Power set: Difference between revisions

=={{header|PowerShell}}==

<lang PowerShell>

function power-set ($array) {

if($array) {

$n = $array.Count

function state($set, $cnt, $i){

if($cnt -lt $n) {

state $set ($cnt + 1) ($i+1)

state ($set+@($array[$i])) ($cnt + 1) ($i+1)

} else {

"$set"

}

}

$set = state @() 0 0

$power = 0..($set.Count-1) | foreach{@(0)}

$i = 0

$set | foreach{$power[$i++] = $_.Split()}

$power

} else {@()}

}

$powerset = power-set @(1,2,3,4)

"number of sets in powerset: $($powerset.Count)"

"sets in powerset:"

$powerset | foreach{"$_"}

$powerset2 = @(@(), @(@()))

"number of sets in powerset2: $($powerset2.Count)"

</lang>

<b>Output:</b>

<pre>

number of sets in powerset: 16

sets in powerset:

4

3

3 4

2

2 4

2 3

2 3 4

1

1 4

1 3

1 3 4

1 2

1 2 4

1 2 3

1 2 3 4

number of sets in powerset2: 2

</pre>