jonas.tngl.sh
Advent of Code solutions in Rust
refactor: introduce `try_from_iter_exact` utility
+39
-4
+1
-2
aoc_2020/src/day14.rs
+1
-2
aoc_2020/src/day14.rs
···
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type Err = anyhow::Error;
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fn from_str(s: &str) -> Result<Self> {
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-
// FIXME: This should use `try_from_iter_exact()`
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-
aoc_utils::array::try_from_iter(s.chars().rev().map(|c| match c {
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aoc_utils::array::try_from_iter_exact(s.chars().rev().map(|c| match c {
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'X' => Ok(None),
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'0' => Ok(Some(false)),
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'1' => Ok(Some(true)),
+1
-2
aoc_2025/src/day12.rs
+1
-2
aoc_2025/src/day12.rs
···
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Ok::<_, ParseIntError>([x.parse()?, y.parse()?])
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.with_context(|| anyhow!("failed to parse region dimenions {dimensions:?}"))
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})?;
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-
// TODO: add try_from_iter_exact
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let presents = aoc_utils::array::try_from_iter(shapes.split_whitespace().map(|s| {
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let presents = aoc_utils::array::try_from_iter_exact(shapes.split_whitespace().map(|s| {
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s.parse()
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.with_context(|| anyhow!("failed to parse present count {s:?}"))
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}))?
+37
aoc_utils/src/array.rs
+37
aoc_utils/src/array.rs
···
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})
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}
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pub fn try_from_iter_exact<T, E, const N: usize>(
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iter: impl IntoIterator<Item = Result<T, E>>,
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) -> Result<Result<[T; N], Vec<T>>, E> {
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let mut n = 0;
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let mut fused = iter.into_iter().fuse();
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let array: [_; N] = try_from_fn(|i| {
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if let Some(elem) = fused.next() {
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n = i + 1;
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Ok(MaybeUninit::new(elem?))
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} else {
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Ok(MaybeUninit::uninit())
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}
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})?;
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+
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Ok(if n != N {
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// received fewer elements from the iterator than N
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Err(array
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.into_iter()
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.take(n)
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.map(|x| unsafe { x.assume_init() })
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.collect())
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} else if let Some(extra) = fused.next() {
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// received at least one more element than expected
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let mut vec: Vec<T> = array
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.into_iter()
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.map(|x| unsafe { x.assume_init() })
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.collect();
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vec.push(extra?);
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for extra in fused {
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vec.push(extra?);
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}
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Err(vec)
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} else {
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Ok(array.map(|x| unsafe { x.assume_init() }))
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})
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}
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+
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pub fn try_map<T, U, E, const N: usize>(
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array: [T; N],
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f: impl FnMut(T) -> Result<U, E>,