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Range consolidation: Difference between revisions
Add source for Rust
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(Add source for Rust) |
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original ranges: []
consolidated ranges: []
</pre>
=={{header|Rust}}==
Most of the implementation below belongs to the test and formatting support.
If the output might be more arbitrary, the source would be quite small.
<lang Rust>use std::fmt::{Display, Formatter};
// We could use std::ops::RangeInclusive, but we would have to extend it to
// normalize self (not much trouble) and it would not have to handle pretty
// printing for it explicitly. So, let's make rather an own type.
#[derive(Clone, Debug, PartialEq, PartialOrd)]
pub struct ClosedRange<Idx> {
start: Idx,
end: Idx,
}
impl<Idx> ClosedRange<Idx> {
pub fn start(&self) -> &Idx {
&self.start
}
pub fn end(&self) -> &Idx {
&self.end
}
}
impl<Idx: PartialOrd> ClosedRange<Idx> {
pub fn new(start: Idx, end: Idx) -> Self {
if start <= end {
Self { start, end }
} else {
Self {
end: start,
start: end,
}
}
}
}
// To make test input more compact
impl<Idx: PartialOrd> From<(Idx, Idx)> for ClosedRange<Idx> {
fn from((start, end): (Idx, Idx)) -> Self {
Self::new(start, end)
}
}
// For the required print format
impl<Idx: Display> Display for ClosedRange<Idx> {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "[{}, {}]", self.start, self.end)
}
}
fn consolidate<Idx>(a: &ClosedRange<Idx>, b: &ClosedRange<Idx>) -> Option<ClosedRange<Idx>>
where
Idx: PartialOrd + Clone,
{
if a.start() <= b.start() {
if b.end() <= a.end() {
Some(a.clone())
} else if a.end() < b.start() {
None
} else {
Some(ClosedRange::new(a.start().clone(), b.end().clone()))
}
} else {
consolidate(b, a)
}
}
fn consolidate_all<Idx>(mut ranges: Vec<ClosedRange<Idx>>) -> Vec<ClosedRange<Idx>>
where
Idx: PartialOrd + Clone,
{
// Panics for incomparable elements! So no NaN for floats, for instance.
ranges.sort_by(|a, b| a.partial_cmp(b).unwrap());
let mut ranges = ranges.into_iter();
let mut result = Vec::new();
if let Some(current) = ranges.next() {
let leftover = ranges.fold(current, |mut acc, next| {
match consolidate(&acc, &next) {
Some(merger) => {
acc = merger;
}
None => {
result.push(acc);
acc = next;
}
}
acc
});
result.push(leftover);
}
result
}
#[cfg(test)]
mod tests {
use super::{consolidate_all, ClosedRange};
use std::fmt::{Display, Formatter};
struct IteratorToDisplay<F>(F);
impl<F, I> Display for IteratorToDisplay<F>
where
F: Fn() -> I,
I: Iterator,
I::Item: Display,
{
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
let mut items = self.0();
if let Some(item) = items.next() {
write!(f, "{}", item)?;
for item in items {
write!(f, ", {}", item)?;
}
}
Ok(())
}
}
macro_rules! parameterized {
($($name:ident: $value:expr,)*) => {
$(
#[test]
fn $name() {
let (input, expected) = $value;
let expected: Vec<_> = expected.into_iter().map(ClosedRange::from).collect();
let output = consolidate_all(input.into_iter().map(ClosedRange::from).collect());
println!("{}: {}", stringify!($name), IteratorToDisplay(|| output.iter()));
assert_eq!(expected, output);
}
)*
}
}
parameterized! {
single: (vec![(1.1, 2.2)], vec![(1.1, 2.2)]),
touching: (vec![(6.1, 7.2), (7.2, 8.3)], vec![(6.1, 8.3)]),
disjoint: (vec![(4, 3), (2, 1)], vec![(1, 2), (3, 4)]),
overlap: (vec![(4.0, 3.0), (2.0, 1.0), (-1.0, -2.0), (3.9, 10.0)], vec![(-2.0, -1.0), (1.0, 2.0), (3.0, 10.0)]),
integer: (vec![(1, 3), (-6, -1), (-4, -5), (8, 2), (-6, -6)], vec![(-6, -1), (1, 8)]),
}
}
fn main() {
// To prevent dead code and to check empty input
consolidate_all(Vec::<ClosedRange<usize>>::new());
println!("Run: cargo test -- --nocapture");
}</lang>
{{out}}
<pre>
running 5 tests
integer: [-6, -1], [1, 8]
disjoint: [1, 2], [3, 4]
single: [1.1, 2.2]
touching: [6.1, 8.3]
overlap: [-2, -1], [1, 2], [3, 10]
test tests::integer ... ok
test tests::disjoint ... ok
test tests::single ... ok
test tests::touching ... ok
test tests::overlap ... ok
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
</pre>
Line 1,606 ⟶ 1,783:
(s:=List()).append(
normalize(rs).reduce('wrap(ab,cd){
}) )
}
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