johannes/advent-of-rust-2024
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day 8 part 2

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Johannes
2024-12-08 07:58:02 +01:00
parent a0c558032b
commit d1f49d204f
1 changed files with 39 additions and 4 deletions
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43
src/day08.rs
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@@ -20,7 +20,7 @@ fn part1(input: &str) -> RiddleResult {
.entries()
.filter(|(_, c)| **c != '.')
.into_group_map_by(|(_, c)| *c);
for (frequency, coords) in antennas {
for (_, coords) in antennas {
for (a, _) in coords.iter() {
for (b, _) in coords.iter() {
if a == b {
@@ -38,8 +38,43 @@ fn part1(input: &str) -> RiddleResult {
antinodes.len()
}
fn part2(_input: &str) -> RiddleResult {
0
fn part2(input: &str) -> RiddleResult {
let grid = Grid::parse(input);
let mut antinodes = HashSet::new();
let antennas = grid
.entries()
.filter(|(_, c)| **c != '.')
.into_group_map_by(|(_, c)| *c);
for (_, coords) in antennas {
for (a, _) in coords.iter() {
for (b, _) in coords.iter() {
if a == b {
continue;
}
antinodes.insert(*a);
antinodes.insert(*b);
let dx = a.0 - b.0;
let dy = a.1 - b.1;
for i in 1.. {
let p = (a.0 + i * dx, a.1 + i * dy);
if grid.contains_key(p) {
antinodes.insert(p);
} else {
break;
}
}
for i in 1.. {
let p = (a.0 - i * dx, a.1 - i * dy);
if grid.contains_key(p) {
antinodes.insert(p);
} else {
break;
}
}
}
}
}
antinodes.len()
}
#[cfg(test)]
@@ -67,6 +102,6 @@ mod test {
#[test]
fn test2() {
assert_eq!(part2(TEST_INPUT), 0);
assert_eq!(part2(TEST_INPUT), 34);
}
}