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Power set: Difference between revisions
→{{header|Rust}}
Line 3,410:
#<Set: {#<Set: {}>, #<Set: {1}>, #<Set: {2}>, #<Set: {1, 2}>, #<Set: {3}>, #<Set: {1, 3}>, #<Set: {2, 3}>, #<Set: {1, 2, 3}>}>
</pre>
=={{header|Rust}}==
This implementation consumes the input set, requires that the type <b>T</b> has a full order a.k.a implements the <b>Ord</b> trait and that <b>T</b> is clonable.
<lang rust>use std::collections::BTreeSet;
fn powerset<T: Ord + Clone>(mut set: BTreeSet<T>) -> BTreeSet<BTreeSet<T>> {
if set.is_empty() {
let mut powerset = BTreeSet::new();
powerset.insert(set);
return powerset;
}
// Access the first value. This could be replaced with `set.pop_first().unwrap()`
// But this is an unstable feature
let entry = set.iter().nth(0).unwrap().clone();
set.remove(&entry);
let mut powerset = powerset(set);
for mut set in powerset.clone().into_iter() {
set.insert(entry.clone());
powerset.insert(set);
}
powerset
}
fn main() {
let set = (0..5).collect();
let set = powerset(set);
println!("{:?}", set);
}
</lang>
{{out}}
<pre>{{}, {0}, {0, 1}, {0, 1, 2}, {0, 1, 2, 3}, {0, 1, 2, 3, 4}, {0, 1, 2, 4}, {0, 1, 3}, {0, 1, 3, 4}, {0, 1, 4}, {0, 2}, {0, 2, 3}, {0, 2, 3, 4}, {0, 2, 4}, {0, 3}, {0, 3, 4}, {0, 4}, {1}, {1, 2}, {1, 2, 3}, {1, 2, 3, 4}, {1, 2, 4}, {1, 3}, {1, 3, 4}, {1, 4}, {2}, {2, 3}, {2, 3, 4}, {2, 4}, {3}, {3, 4}, {4}}
</pre>
=={{header|SAS}}==
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