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day5: reimplement in a sane, fast way

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This commit is contained in:
Keenan Tims
2023-12-15 18:10:29 -08:00
parent 84bcbd550b
commit 498c96eaeb
3 changed files with 247 additions and 75 deletions
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142
5/src/main.rs
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@@ -153,16 +153,16 @@ fn main() {
#[derive(Debug)]
struct AlmanacMapping {
source_range: Range<u64>,
dest_range: Range<u64>,
source_range: Range<i64>,
dest_range: Range<i64>,
}
impl From<&str> for AlmanacMapping {
fn from(s: &str) -> Self {
let s_nums: Vec<_> = s.split_whitespace().take(3).collect();
let length: u64 = s_nums[2].parse().unwrap();
let source_start: u64 = s_nums[1].parse().unwrap();
let dest_start: u64 = s_nums[0].parse().unwrap();
let length: i64 = s_nums[2].parse().unwrap();
let source_start: i64 = s_nums[1].parse().unwrap();
let dest_start: i64 = s_nums[0].parse().unwrap();
AlmanacMapping {
source_range: source_start..source_start + length,
dest_range: dest_start..dest_start + length,
@@ -171,7 +171,7 @@ impl From<&str> for AlmanacMapping {
}
impl AlmanacMapping {
fn lookup(&self, key: u64) -> Option<u64> {
fn lookup(&self, key: i64) -> Option<i64> {
if self.source_range.contains(&key) {
Some(self.dest_range.start + (key - self.source_range.start))
} else {
@@ -186,13 +186,74 @@ struct AlmanacMappingTable {
mappings: Vec<AlmanacMapping>,
}
fn range_overlap<T: num::Num + Ord + Copy>(r1: &Range<T>, r2: &Range<T>) -> Option<Range<T>> {
let new_start = std::cmp::max(r1.start, r2.start);
let new_end = std::cmp::min(r1.end - T::one(), r2.end - T::one());
if new_start <= std::cmp::min(r1.end - T::one(), r2.end - T::one())
&& new_end >= std::cmp::max(r1.start, r2.start)
{
Some(new_start..new_end + T::one())
} else {
None
}
}
fn range_exclude<T: num::Num + Ord + Copy>(keep: &Range<T>, exclude: &Range<T>) -> Vec<Range<T>> {
let mut residual = Vec::new();
if let Some(overlap) = range_overlap(keep, exclude) {
if keep.start < overlap.start {
residual.push(keep.start..overlap.start);
}
if keep.end > overlap.end {
residual.push(overlap.end..keep.end);
}
} else {
residual.push(keep.clone());
}
residual
}
impl AlmanacMappingTable {
fn lookup(&self, key: u64) -> u64 {
fn lookup(&self, key: i64) -> i64 {
self.mappings
.iter()
.find_map(|map| map.lookup(key))
.unwrap_or(key)
}
fn lookup_ranges(&self, ranges: Vec<Range<i64>>) -> Vec<Range<i64>> {
ranges
.iter()
.flat_map(|range| self.lookup_range(range))
.collect()
}
fn lookup_range(&self, range: &Range<i64>) -> Vec<Range<i64>> {
let mut residual = vec![range.clone()];
let mut resolved_mappings = Vec::new();
for map in &self.mappings {
let mut local_residual = Vec::new();
for range in residual.into_iter() {
if let Some(overlap) = range_overlap(&range, &map.source_range) {
let dest_start_idx = overlap.start - map.source_range.start;
let length = overlap.end.saturating_sub(overlap.start);
resolved_mappings.push(
(map.dest_range.start + dest_start_idx)
..(map.dest_range.start + dest_start_idx + length),
);
local_residual.extend_from_slice(&range_exclude(&range, &overlap));
} else {
local_residual.push(range);
}
}
residual = local_residual;
}
// unresolved maps map 1:1
resolved_mappings.extend_from_slice(&residual);
resolved_mappings
}
}
impl<T: BufRead> From<&mut Lines<T>> for AlmanacMappingTable {
@@ -218,7 +279,7 @@ impl<T: BufRead> From<&mut Lines<T>> for AlmanacMappingTable {
#[derive(Debug)]
struct Almanac {
seeds: Vec<u64>,
seeds: Vec<i64>,
seed_to_soil: AlmanacMappingTable,
soil_to_fertilizer: AlmanacMappingTable,
fertilizer_to_water: AlmanacMappingTable,
@@ -231,7 +292,7 @@ struct Almanac {
impl<T: BufRead> From<Lines<T>> for Almanac {
fn from(mut lines: Lines<T>) -> Self {
let seeds_s = lines.next().unwrap().unwrap();
let seeds: Vec<u64> = seeds_s
let seeds: Vec<i64> = seeds_s
.split_once(": ")
.unwrap()
.1
@@ -254,7 +315,7 @@ impl<T: BufRead> From<Lines<T>> for Almanac {
}
impl Almanac {
fn lookup(&self, seed_id: u64) -> u64 {
fn lookup(&self, seed_id: i64) -> i64 {
self.humidity_to_location.lookup(
self.temperature_to_humidity.lookup(
self.light_to_temperature.lookup(
@@ -268,6 +329,20 @@ impl Almanac {
),
)
}
fn lookup_range(&self, range: Range<i64>) -> Vec<Range<i64>> {
self.humidity_to_location.lookup_ranges(
self.temperature_to_humidity.lookup_ranges(
self.light_to_temperature.lookup_ranges(
self.water_to_light.lookup_ranges(
self.fertilizer_to_water.lookup_ranges(
self.soil_to_fertilizer
.lookup_ranges(self.seed_to_soil.lookup_ranges(vec![range])),
),
),
),
),
)
}
}
// PROBLEM 1 solution
@@ -287,7 +362,7 @@ impl Almanac {
// What is the lowest location number that corresponds to any of the initial seed numbers?
fn problem1_lowest_location(almanac: &Almanac) -> u64 {
fn problem1_lowest_location(almanac: &Almanac) -> i64 {
almanac
.seeds
.iter()
@@ -296,7 +371,7 @@ fn problem1_lowest_location(almanac: &Almanac) -> u64 {
.unwrap()
}
fn problem1<T: BufRead>(input: Lines<T>) -> u64 {
fn problem1<T: BufRead>(input: Lines<T>) -> i64 {
let almanac = Almanac::from(input);
problem1_lowest_location(&almanac)
}
@@ -327,33 +402,40 @@ fn problem1<T: BufRead>(input: Lines<T>) -> u64 {
// the almanac. What is the lowest location number that corresponds to any of the
// initial seed numbers?
fn problem2_lowest_location(almanac: &Almanac) -> u64 {
fn problem2_lowest_location(almanac: &Almanac) -> i64 {
let seed_ranges = almanac
.seeds
.iter()
.tuples()
.map(|(range_start, length)| *range_start..*range_start + *length);
seed_ranges
.map(|range| {
range
.into_par_iter()
.map(|x| almanac.lookup(x))
.min()
.unwrap()
})
.min()
.unwrap()
// seed_ranges
// .map(|range| {
// range
// .into_par_iter()
// .map(|x| almanac.lookup(x))
// .min()
// .unwrap()
// })
// .min()
// .unwrap()
let ranges = seed_ranges
.flat_map(|range| almanac.lookup_range(range))
.collect_vec();
ranges.iter().map(|range| range.start).min().unwrap()
}
fn problem2<T: BufRead>(input: Lines<T>) -> u64 {
fn problem2<T: BufRead>(input: Lines<T>) -> i64 {
let almanac = Almanac::from(input);
problem2_lowest_location(&almanac)
}
#[cfg(test)]
mod tests {
use num::Num;
use std::io::{BufRead, Cursor};
use test_case::test_case;
use crate::*;
@@ -413,6 +495,18 @@ humidity-to-location map:
assert_eq!(a.lookup(79), 82);
}
#[test_case(0..5, 2..4, Some(2..4) ; "one range overlaps completely")]
#[test_case(0..5, 2..10, Some(2..5) ; "one range overlaps from below")]
#[test_case(0..5, 5..10, None ; "no overlap, touching")]
#[test_case(0..5, 6..10, None ; "no overlap, disjoint")]
fn test_range_overlap<T: Num + Copy + Ord + std::fmt::Debug>(
r1: Range<T>,
r2: Range<T>,
expected: Option<Range<T>>,
) {
assert_eq!(range_overlap(&r1, &r2), expected);
}
#[test]
fn test_problem1_example() {
let c = Cursor::new(EXAMPLE_ALMANAC);