solve day 11

2023/day11/src/faster.rs

@@ -0,0 +1,70 @@
+use std::cmp::{max, min};
+
+use helper::IteratorExt;
+
+use crate::Universe;
+
+fn height_width(universe: &Universe, count: u64) -> (Vec<u64>, Vec<u64>) {
+    let rows = universe
+        .rows
+        .iter()
+        .map(|row| if row.iter().all(|b| !b) { count } else { 1 })
+        .collect_vec();
+
+    let cols = (0..universe.rows[0].len())
+        .map(|col| {
+            if universe.rows.iter().all(|row| !row[col]) {
+                count
+            } else {
+                1
+            }
+        })
+        .collect_vec();
+
+    (rows, cols)
+}
+
+fn solve(input: &str, count: u64) -> u64 {
+    let universe = super::parse(input);
+    let (row_height, col_width) = height_width(&universe, count);
+
+    let galaxies = universe
+        .rows
+        .iter()
+        .enumerate()
+        .flat_map(|(i, row)| {
+            row.iter()
+                .copied()
+                .enumerate()
+                .filter(|&(_, b)| b)
+                .map(move |(j, _)| (i, j))
+        })
+        .collect_vec();
+
+    let mut sum = 0;
+
+    for i in 0..galaxies.len() {
+        for j in (i + 1)..galaxies.len() {
+            let lhs = galaxies[i];
+            let rhs = galaxies[j];
+
+            let x_range = min(lhs.1, rhs.1)..max(lhs.1, rhs.1);
+            let distance_x = x_range.map(|x| col_width[x]).sum::<u64>();
+
+            let y_range = min(lhs.0, rhs.0)..max(lhs.0, rhs.0);
+            let distance_y = y_range.map(|x| row_height[x]).sum::<u64>();
+
+            sum += distance_x + distance_y;
+        }
+    }
+
+    sum as u64
+}
+
+pub fn part1(input: &str) -> u64 {
+    solve(input, 2)
+}
+
+pub fn part2(input: &str) -> u64 {
+    solve(input, 1_000_000)
+}

2023/day11/src/lib.rs

@@ -1,3 +1,6 @@
+mod faster;
+mod p1slow;
+
 use std::fmt::Debug;
 
 use helper::{Day, IteratorExt, Variants};
@@ -11,10 +14,11 @@ struct Day11;
 helper::define_variants! {
     day => crate::Day11;
     part1 {
-        basic => crate::part1;
+        basic => crate::p1slow::part1;
+        faster => crate::faster::part1, sample_count=200;
     }
     part2 {
-        basic => crate::part2;
+        basic => crate::faster::part2, sample_count=200;
     }
 }
 
@@ -54,78 +58,15 @@ fn parse(input: &str) -> Universe {
     }
 }
 
-fn expand(universe: Universe) -> Universe {
-    let mut rows = universe
-        .rows
-        .into_iter()
-        .flat_map(|row| {
-            if row.iter().all(|b| !b) {
-                vec![row.clone(), row]
-            } else {
-                vec![row]
-            }
-        })
-        .collect_vec();
-
-    let mut col = 0;
-    while col < rows[0].len() {
-        if rows.iter().all(|row| !row[col]) {
-            rows.iter_mut().for_each(|row| row.insert(col, false));
-            col += 1;
-        }
-        col += 1;
-    }
-
-    Universe { rows }
-}
-
-fn part1(input: &str) -> u64 {
-    let universe = parse(input);
-    let universe = expand(universe);
-
-    let galaxies = universe
-        .rows
-        .iter()
-        .enumerate()
-        .flat_map(|(i, row)| {
-            row.iter()
-                .copied()
-                .enumerate()
-                .filter(|&(_, b)| b)
-                .map(move |(j, _)| (i, j))
-        })
-        .collect_vec();
-
-    let mut sum = 0;
-
-    for i in 0..galaxies.len() {
-        for j in (i + 1)..galaxies.len() {
-            let lhs = galaxies[i];
-            let rhs = galaxies[j];
-
-            let distance_x = ((lhs.1 as i64) - (rhs.1 as i64)).abs();
-            let distance_y = ((lhs.0 as i64) - (rhs.0 as i64)).abs();
-
-            sum += distance_x + distance_y;
-        }
-    }
-
-    sum as u64
-}
-
-fn part2(_input: &str) -> u64 {
-    0
-}
-
 helper::tests! {
     day11 Day11;
     part1 {
         small => 374;
-        default => 0;
+        default => 9370588;
     }
     part2 {
-        small => 0;
+        small => 82000210;
-        default => 0;
+        default => 746207878188;
     }
 }
 helper::benchmarks! {}

2023/day11/src/p1slow.rs

@@ -0,0 +1,62 @@
+use helper::IteratorExt;
+
+use crate::Universe;
+
+fn expand(universe: Universe) -> Universe {
+    let mut rows = universe
+        .rows
+        .into_iter()
+        .flat_map(|row| {
+            if row.iter().all(|b| !b) {
+                vec![row.clone(), row]
+            } else {
+                vec![row]
+            }
+        })
+        .collect_vec();
+
+    let mut col = 0;
+    while col < rows[0].len() {
+        if rows.iter().all(|row| !row[col]) {
+            rows.iter_mut().for_each(|row| row.insert(col, false));
+            col += 1;
+        }
+        col += 1;
+    }
+
+    Universe { rows }
+}
+
+pub fn part1(input: &str) -> u64 {
+    let universe = super::parse(input);
+    let universe = expand(universe);
+
+    let galaxies = universe
+        .rows
+        .iter()
+        .enumerate()
+        .flat_map(|(i, row)| {
+            row.iter()
+                .copied()
+                .enumerate()
+                .filter(|&(_, b)| b)
+                .map(move |(j, _)| (i, j))
+        })
+        .collect_vec();
+
+    let mut sum = 0;
+
+    for i in 0..galaxies.len() {
+        for j in (i + 1)..galaxies.len() {
+            let lhs = galaxies[i];
+            let rhs = galaxies[j];
+
+            let distance_x = ((lhs.1 as i64) - (rhs.1 as i64)).abs();
+            let distance_y = ((lhs.0 as i64) - (rhs.0 as i64)).abs();
+
+            sum += distance_x + distance_y;
+        }
+    }
+
+    sum as u64
+}