2022 day 23 rust

2022/rust/inputs/day23.txt

@@ -0,0 +1,73 @@
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2022/rust/src/solutions/day23.rs

@@ -1,4 +1,4 @@
-use std::collections::HashSet;
+use std::collections::{HashMap, HashSet, VecDeque};
 use crate::utils;
 
 
@@ -11,26 +11,154 @@ pub fn run() -> () {
 }
 
 
-type Location = (isize, isize);
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
-
+struct Loc {
-
+    row: isize,
-fn solve1(data: &HashSet<Location>) -> i32 {
+    col: isize
-    println!("{:?}", data);
-    1
 }
 
-fn solve2(data: &HashSet<Location>) -> i32 {
+impl Loc {
-    2
+    fn n(&self) -> Self { Self { row: self.row - 1, col: self.col } }
+    fn s(&self) -> Self { Self { row: self.row + 1, col: self.col } }
+    fn w(&self) -> Self { Self { row: self.row, col: self.col - 1 } }
+    fn e(&self) -> Self { Self { row: self.row, col: self.col + 1 } }
+    fn nw(&self) -> Self { Self { row: self.row - 1, col: self.col - 1 } }
+    fn ne(&self) -> Self { Self { row: self.row - 1, col: self.col + 1 } }
+    fn sw(&self) -> Self { Self { row: self.row + 1, col: self.col - 1 } }
+    fn se(&self) -> Self { Self { row: self.row + 1, col: self.col + 1 } }
+}
+
+fn has_neighbors(occupied: &HashSet<Loc>, loc: Loc) -> bool {
+    [loc.n(), loc.s(), loc.w(), loc.e(), loc.nw(), loc.ne(), loc.sw(), loc.se()].into_iter().any(|loc| occupied.contains(&loc))
+}
+
+fn move_n(occupied: &HashSet<Loc>, loc: Loc) -> Option<Loc> {
+    let nn = !occupied.contains(&loc.n());
+    let ne = !occupied.contains(&loc.ne());
+    let nw = !occupied.contains(&loc.nw());
+    (nn && ne && nw).then_some(loc.n())
+}
+
+fn move_s(occupied: &HashSet<Loc>, loc: Loc) -> Option<Loc> {
+    let ss = !occupied.contains(&loc.s());
+    let se = !occupied.contains(&loc.se());
+    let sw = !occupied.contains(&loc.sw());
+    (ss && se && sw).then_some(loc.s())
+}
+
+fn move_w(occupied: &HashSet<Loc>, loc: Loc) -> Option<Loc> {
+    let ww = !occupied.contains(&loc.w());
+    let nw = !occupied.contains(&loc.nw());
+    let sw = !occupied.contains(&loc.sw());
+    (ww && nw && sw).then_some(loc.w())
+}
+
+fn move_e(occupied: &HashSet<Loc>, loc: Loc) -> Option<Loc> {
+    let ee = !occupied.contains(&loc.e());
+    let ne = !occupied.contains(&loc.ne());
+    let se = !occupied.contains(&loc.se());
+    (ee && ne && se).then_some(loc.e())
+}
+
+fn find_bounds(locs: &HashSet<Loc>) -> ((isize, isize), (isize, isize)) {
+    locs.iter().fold(((isize::MAX, isize::MIN), (isize::MAX, isize::MIN)), |((r_min, r_max), (c_min, c_max)), loc| {
+        ((r_min.min(loc.row), r_max.max(loc.row)), (c_min.min(loc.col), c_max.max(loc.col)))
+    })
+}
+
+fn draw(elves: &Vec<Loc>) {
+    let elves = HashSet::<Loc>::from_iter(elves.iter().copied());
+    let ((r_min, r_max), (c_min, c_max)) = find_bounds(&elves);
+
+    for row in r_min..=r_max {
+        for col in c_min..=c_max {
+            match elves.contains(&Loc { row, col }) {
+                true => print!("#"),
+                false => print!("."),
+            }
+        }
+        println!();
+    }
+}
+
+fn count_empty(elves: &Vec<Loc>) -> i32 {
+    let elves = HashSet::<Loc>::from_iter(elves.iter().copied());
+    let ((r_min, r_max), (c_min, c_max)) = find_bounds(&elves);
+
+    let mut sum = 0;
+    for row in r_min..=r_max {
+        for col in c_min..=c_max {
+            if !elves.contains(&Loc { row, col }) {
+                sum += 1;
+            }
+        }
+    }
+    sum
+}
+
+fn solve1(data: &HashSet<Loc>) -> i32 {
+    let mut elves = Vec::from_iter(data.iter().copied());
+    let mut moves = VecDeque::from([move_n, move_s, move_w, move_e]);
+
+    for _ in 0..10 {
+        let occupied = HashSet::<Loc>::from_iter(elves.iter().copied());
+        let mut planned = HashMap::<Loc, Vec<usize>>::new();
+        for (index, &loc) in elves.iter().enumerate().filter(|&(_, loc)| has_neighbors(&occupied, *loc)) {
+            if let Some(loc) = moves.iter().filter_map(|f| f(&occupied, loc)).next() {
+                planned.entry(loc)
+                    .and_modify(|v| v.push(index))
+                    .or_insert(vec![index]);
+            }
+        }
+
+        for (loc, planned) in planned.into_iter().filter(|(_, vec)| vec.len() == 1) {
+            elves[planned[0]] = loc;
+        }
+
+        moves.rotate_left(1);
+    }
+
+    count_empty(&elves)
+}
+
+fn solve2(data: &HashSet<Loc>) -> i32 {
+    let mut elves = Vec::from_iter(data.iter().copied());
+    let mut moves = VecDeque::from([move_n, move_s, move_w, move_e]);
+
+    for round in 1..i32::MAX {
+        let occupied = HashSet::<Loc>::from_iter(elves.iter().copied());
+        let mut planned = HashMap::<Loc, Vec<usize>>::new();
+        for (index, &loc) in elves.iter().enumerate().filter(|&(_, loc)| has_neighbors(&occupied, *loc)) {
+            if let Some(loc) = moves.iter().filter_map(|f| f(&occupied, loc)).next() {
+                planned.entry(loc)
+                    .and_modify(|v| v.push(index))
+                    .or_insert(vec![index]);
+            }
+        }
+
+        let changes = planned.into_iter().filter(|(_, vec)| vec.len() == 1).collect::<Vec<_>>();
+        if changes.len() == 0 { return round }
+
+        for (loc, planned) in changes {
+            elves[planned[0]] = loc;
+        }
+
+        moves.rotate_left(1);
+    };
+    panic!()
 }
 
 
-fn parse_data<T: AsRef<str>>(data: &[T]) -> HashSet<Location> {
+fn parse_data<T: AsRef<str>>(data: &[T]) -> HashSet<Loc> {
     data.iter()
         .enumerate()
         .flat_map(|(row, line)| line.as_ref()
             .char_indices()
             .filter(|&(_, c)| c == '#')
-            .map(move |(col, _)| (row as isize, col as isize))
+            .map(move |(col, _)| Loc {
+                row: row as isize,
+                col: col as isize,
+            })
         )
         .collect()
 }
@@ -41,21 +169,27 @@ mod tests {
     use super::*;
 
     static DATA: &[&str] = &[
-        ".....",
+        "..............",
-        "..##.",
+        "..............",
-        "..#..",
+        ".......#......",
-        ".....",
+        ".....###.#....",
-        "..##.",
+        "...#...#.#....",
-        ".....",
+        "....#...##....",
+        "...#.###......",
+        "...##.#.##....",
+        "....#..#......",
+        "..............",
+        "..............",
+        "..............",
     ];
 
     #[test]
     fn part1() {
-        assert_eq!(1, solve1(&parse_data(DATA)));
+        assert_eq!(110, solve1(&parse_data(DATA)));
     }
 
     #[test]
     fn part2() {
-        assert_eq!(2, solve2(&parse_data(DATA)));
+        assert_eq!(20, solve2(&parse_data(DATA)));
     }
 }