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2019: day06: use a HashSet instead

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This commit is contained in:
Antoine Martin 2019-12-06 12:00:37 +01:00
parent 0fa59d675b
commit 6f06d5d7ca
1 changed files with 4 additions and 10 deletions
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14
aoc2019/src/day06.rs
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@ -1,4 +1,5 @@
use std::collections::HashMap; use std::collections::HashMap;
use std::collections::HashSet;
use std::iter; use std::iter;
use aoc::err; use aoc::err;
@ -64,17 +65,10 @@ fn part2(input: &str) -> Result<usize> {
let succ = |key: &String| orbits.get(key).map(|val| val.clone()); let succ = |key: &String| orbits.get(key).map(|val| val.clone());
let you_path = iter::successors(Some("YOU".to_string()), succ).collect::<Vec<_>>(); let you_path = iter::successors(Some("YOU".to_string()), succ).collect::<HashSet<_>>();
let santa_path = iter::successors(Some("SAN".to_string()), succ).collect::<Vec<_>>(); let santa_path = iter::successors(Some("SAN".to_string()), succ).collect::<HashSet<_>>();
let common = you_path Ok(you_path.symmetric_difference(&santa_path).count() - 2)
.iter()
.rev()
.zip(santa_path.iter().rev())
.filter(|(x, y)| x == y)
.count();
Ok(you_path.len() - common + santa_path.len() - common - 2)
} }
#[cfg(test)] #[cfg(test)]