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-rw-r--r--src/bin/2023/day11.rs94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/bin/2023/day11.rs b/src/bin/2023/day11.rs
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+++ b/src/bin/2023/day11.rs
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+#![allow(dead_code)]
+#![allow(unused_variables)]
+
+use advent_of_code::prelude::*;
+
+pub fn parse(fh: File) -> Result<Grid<bool>> {
+ Ok(parse::grid(parse::raw_lines(fh), |c, _, _| c == b'#'))
+}
+
+pub fn part1(mut map: Grid<bool>) -> Result<i64> {
+ let mut expand_rows = vec![];
+ for row in map.each_row() {
+ if map[row].iter().all(|b| !b) {
+ expand_rows.push(row);
+ }
+ }
+ let mut expand_cols = vec![];
+ for col in map.each_col() {
+ if map.each_row().map(|row| map[row][col]).all(|b| !b) {
+ expand_cols.push(col);
+ }
+ }
+ for row in expand_rows.into_iter().rev() {
+ map.insert_row(row);
+ }
+ for col in expand_cols.into_iter().rev() {
+ map.insert_col(col);
+ }
+
+ let galaxies: HashSet<(Row, Col)> = map
+ .indexed_cells()
+ .filter_map(|(pos, galaxy)| if *galaxy { Some(pos) } else { None })
+ .collect();
+
+ let mut total = 0;
+ for a in &galaxies {
+ for b in &galaxies {
+ total += a.0.abs_diff(b.0).0 + a.1.abs_diff(b.1).0
+ }
+ }
+
+ Ok((total / 2).try_into().unwrap())
+}
+
+pub fn part2(map: Grid<bool>) -> Result<i64> {
+ let mut expand_rows = vec![];
+ for row in map.each_row() {
+ if map[row].iter().all(|b| !b) {
+ expand_rows.push(row);
+ }
+ }
+ let mut expand_cols = vec![];
+ for col in map.each_col() {
+ if map.each_row().map(|row| map[row][col]).all(|b| !b) {
+ expand_cols.push(col);
+ }
+ }
+
+ let galaxies: HashSet<(Row, Col)> = map
+ .indexed_cells()
+ .filter_map(|(pos, galaxy)| if *galaxy { Some(pos) } else { None })
+ .collect();
+
+ let mut total = 0;
+ for a in &galaxies {
+ for b in &galaxies {
+ let expanded_rows = expand_rows
+ .iter()
+ .filter(|row| (a.0.min(b.0)..a.0.max(b.0)).contains(row))
+ .count();
+ let expanded_cols = expand_cols
+ .iter()
+ .filter(|col| (a.1.min(b.1)..a.1.max(b.1)).contains(col))
+ .count();
+ total += a.0.abs_diff(b.0).0
+ + a.1.abs_diff(b.1).0
+ + 999999 * (expanded_rows + expanded_cols);
+ }
+ }
+
+ Ok((total / 2).try_into().unwrap())
+}
+
+#[test]
+fn test() {
+ assert_eq!(
+ part1(parse(parse::data(2023, 11).unwrap()).unwrap()).unwrap(),
+ 10033566
+ );
+ assert_eq!(
+ part2(parse(parse::data(2023, 11).unwrap()).unwrap()).unwrap(),
+ 560822911938
+ );
+}