From 3b877bf4cc667eb8bcc787d145203600a4dba2d2 Mon Sep 17 00:00:00 2001 From: Prefetch Date: Sat, 25 Feb 2023 11:41:27 +0100 Subject: Initial commit --- d24/Cargo.toml | 7 +++ d24/input.txt | 39 +++++++++++++++ d24/src/main.rs | 146 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 192 insertions(+) create mode 100644 d24/Cargo.toml create mode 100644 d24/input.txt create mode 100644 d24/src/main.rs (limited to 'd24') diff --git a/d24/Cargo.toml b/d24/Cargo.toml new file mode 100644 index 0000000..800c124 --- /dev/null +++ b/d24/Cargo.toml @@ -0,0 +1,7 @@ +[package] +name = "d24" +version = "0.1.0" +edition = "2021" + +[dependencies] +itertools = "0.10.5" diff --git a/d24/input.txt b/d24/input.txt new file mode 100644 index 0000000..6fcc4f5 --- /dev/null +++ b/d24/input.txt @@ -0,0 +1,39 @@ +##################################################################################################################################################################################### +#.....#.#.....#.#.#...#.....#.#.#.#.....#3......#...........#.#.....#.....#.............#.#...#...#.....#...#.........#.#...............#.....#.....#.........................#.....# +#.#.#.#.#.#.#.#.#.#.#.#.###.#.#.#.#.#.#####.#.#.#.#####.#.###.#.#.###.#.#####.###.#.#.#.#.#####.#.#.#.#####.#.#.#####.#.#.#####.###.#.#.###.###.###.#.###.#.###.###.#.#######.####### +#.....#...#.#.....#...#.........#...........#.......#...#.#.....#.....#.#.#.......#...#.#...#...#...#.#...#...#.#...#.#.#.#.......#...#...#.....#.....#.....#...#...#.......#.#...#.# +###.#####.#.#######.###.#.#.#.#.#.#####.#.#.#.#####.#.###.#.#####.#.#.#.#.#####.#.#.#.#.#.###.#.###.#.#####.#.#.#.#.###.#.#.#.###.#.#.#.#.###.#.#.###.#.#.#.#.#.#.#.#.#.#####.#.#.#.# +#...#1......#.....#.#.#.#.....#.#.#.....#...#.#...#.......#...........#.............#...#.....#.......#.....#.....#.#.......#.#...#.#.#.#.......#...#.#...........#.#.....#...#.#...# +#.#.###.#.###.#.#.#.#.#.#.#######.#.#.###.#.#.#.###.#####.###.#.#.#.#.#.###.#.#####.#.#.#####.#####.#.#.#.#.#.#.#.###.###.#.#####.#.#.#####.#.#.#.#.#.#.#.###.#####.###.#.#.#.#.###.# +#.....#.#.....#.#...#.#.....#.#.#.#.........#.#.#.......#.#.#.......#...#...#...#.....#.#...#.......#.....#.......#...#.....#...#...#.......#...#.#.....#...#.#.....#.#...#.#...#...# +#.#.#.#.#####.#.###.#.#.#.###.#.###.#.#.#####.#.#####.#.#.#.#.#####.#.#.#.###.#######.#.###.#.###.#.#.#.#.#.#.#####.###.#####.#.#.#.#.#####.#####.#.###.#.#.#.#.#.#.#.#####.###.#.### +#...#.#...#.........#.#...#.#...#.....#.#.....#.......#.........#.....#.....#.........#.....#...#.#.#.#.....#.#.................#.#.#.......#.......#.......#...#...#.......#.#...#.# +#.#.#.#.#.#.#.###.#.###.###.#.#.#.###.###.#.#.#.#.#.#.#########.#.###.#.#.#####.#.#.#.###.#######.#.###.#.#.#.#.#.#.#.###.#.#.###.#######.#.###.#.#.#.#.###.#.#.#.#####.###.#.#.###.# +#...#.#.#.#.#...#...#...#.............#.....#.....#...#...#.#.....#...#...#.....#.#.....#...#...........#.#.#.#.......#...#.............#...#.#...#...........#...#2#...#.....#.#.#.# +###.###.#.#####.#.#.#.#.#.#.#.#.#.#.###.###.#.#.#.###.###.#.#.#.#.#.#.###.###.#.#.#.#.###.#.#.#.###.#####.###.###.#.#.#.###.#######.###.###.#.#.#.#####.#####.###.#.#.#####.#.#.#.### +#.......#...#...........#.......#...#.#.......#.....#.....#...#...#.#.........#.......#...#.#...#...........#.#...#.#...............#.#.#.....#.......#.#.#.#.....#.........#.#.#.#.# +###.#.#.#.#.#.#.#####.###.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#####.#.###.#.###.#.#.#.#########.###.#.###.#.###.#.#.#.#.#######.#####.###.#.#.#.#.#####.#####.#.#.#.#.#.#######.#.###.#.#.#.# +#...#.....#.#.............#...#.#.....#.#...#.......#.........#...#...#.#...#...........#...#...........#...#...#.................#...#.#.#.....#.......#.#.#.......#...#...#...#...# +###.#.#######.#.#.#.###.#.#.#.###.#.#.#.#.#.###.#####.#.###.#.#.#.###.#.#.#.#.#.#.#.###.#.#.#.#.#.#.#####.#.#####.#.#.#.#.#.#######.#.#.#.###.#.#.#.#.#.###.#.###.#########.###.#.#.# +#.....#...#.....#.....#...#.........#.#...#.....#...#.................#...#.#.#.......#.....#...#.#.................#.#.#.........#.....#...#.#...#.....#.................#.#.....#.# +#.#####.#.#.#####.###.#.#.#.###.###.#.#########.#.#######.###.###.#.#.#.#.#.#.#.###.#.#.#####.#.###.#.#########.#.###.###.#.###.###.#.#.#.#.#.###.#####.#.#.#######.#.###.#.#.###.### +#0#...#.#...#...........#.#.............#.#.......#.....#.#.#.....#.#.#...#.....#.#.#.......#.#...#.................#.#.#.....#...#.#.........#.......#.#...#.......#.......#.....#.# +#####.#.###.#.#.###.#####.###.#######.###.#.#.###.#.#.#.#.#.#.#.#.###.#.#.#.#.#.#.#.#.#####.###.#.#####.#.#.#.###.#.#.#.#########.#.#.#.###.#.#.###.#.#####.#.#.#.#.#.###.###.#.#.#.# +#...#.#.....#.#.#...#.......#.#.#...#.........#.......#...#.#.....#.............#...........#...#.#.......#.#.....#.#...........#...#.........#.#...#.#.....#.......#...#.......#...# +###.###.###.#.###.###.#.###.###.#.#.#.#########.#####.###.#######.#.###.#.#.#.###.#.#.#.#.#.#.#.#####.###.#.#.#.#.#.#.#####.###.#.#.###.#####.#.#.#####.#.#.###.#.#####.#.#.#.#.#.#.# +#.......#...............#.....#...#...#.#...#.........#...........#.....#.....#.......#...#.....#.......#.#.#.#...#...............#.....#.....#...#.#...#...#.#.#.#.#.....#...#.#.#4# +#.#.#.#.#.#####.###.#.#####.#.###.#.###.#.#.#.###.###.#.#####.#.#####.#.#######.#.#####.#.#######.#.###.#.#.#.###.###.###.#####.#.###.#.#.#.#####.#.#.#.###.#.#.###.###.#.#.#.#.#.### +#...#...........#.......#...#.....#.#.......#.....#.........#.#.......#.#...#...#...........#.......#.....#...#...#...#.#...#.....#...#.........#...#...#.....#.....#...#...#...#...# +###.#.###.#############.#.###.###.#.###.#.#.#.#.#.#.#.#.###.#####.#.#.#.#.#.#####.###.#.#.#.#.###.#.#.#.#.#.###.#.#.###.#.#.#.###.###.#.#.###.#.#.#.#.#.#.#####.#.#.#.#.#.#.###.#.### +#...#.....#.#...#.#.#.#...........#.......#...#.....#...#...................#...#...#.#.#.#...#.......#...............#...#...#...#...#.#.#5#...#...#.#...#...#.#...#.#...#...#.#...# +#.###.###.#.#.#.#.#.#.###.#.#######.#.#.#.###.#.#.#.#.#.#.###.#.###.###.#.#.#.#.#.###.#.#.#.#.#.###.#.#.###.#.#.###.#.#.#.#.#.#.#.#.#####.#.#.#######.#.#.#.#.#.#####.#.#######.#.#.# +#.........#.#...#.#...#...#.............#.....#...#.#.#.#.#.#.....#.#...#.....#.#.#.........#.....#.........#.....#...........#...#.........#.....#...#.#.#.#...#...........#...#...# +#.#.#.#######.#.#####.#.#.#.###.#.#######.#####.#.#.###.#.#.#.###.###.#.###.#.#.#.###.#.#.#.#####.#.###.#.#.#.#.#.#.#####.#.#.###.#.#.#.#.#####.###.#####.#.#.#.#.###.#.#.#####.##### +#...#...............#.#.......#.......#.......#.........#.#.#.#...#...#...#.......#.#.....#.#...........#...#.#.#...........#.#...#.......#.........#...#...#.....#...#.#.....#.#...# +###.#.#.#.#.#########.#.#.#.#.#.#####.#.#######.#.###.#.#.#.###.###.#.#.#.#.#.###.#.#.###.#.#####.#.###########.#.#.#####.#####.#####.#####.#.#.#.#.#.#.#####.#.#.#########.#.###.#.# +#.#...#.....#.......#.....#...#.......#.#.#...#...#...#.........#...#...#.#...#.#.........#.#.......#.#.#...#...#.........#.#.........#.....#.#.#...#.......#.#.....#.......#.#.....# +#.#.###.#.###.#.#.#.#.###.#########.#.#.#.#.#.#.###.#.#.#####.#.#.#####.#####.#.#.#########.#.#.#.###.#.#####.#.#.###.###.#.#.#.#.#.#####.###.#.###########.#.#.#.#.#.#######.#####.# +#........7#.....#.#...#.#.#.#.........#...#.#...........#.....#.......#.........#.........#.....#.......#.#.......#.#.#...#...#.#.#....6#.#.........................#...#.#.......#.# +#.###.#.###.###.###.#.#.###.###.#####.###.#.#.###.#####.###.#.###.#.#.#.#.#.#.#.#.#####.#.#.#####.#######.#.###.#.#.#####.#####.#.#.#.###.#.#.#.#.#####.#.#.###.#####.#.#.#.#.#.#.#.# +#.#...#.#...#.#.....#.#.......#...#.....#...#...#...#...#.#.....#...#.#...#...#...#.#.............#.............#.#...#.............#.#.....#.....#.......#.#.#.#.........#...#...#.# +##################################################################################################################################################################################### diff --git a/d24/src/main.rs b/d24/src/main.rs new file mode 100644 index 0000000..a43866b --- /dev/null +++ b/d24/src/main.rs @@ -0,0 +1,146 @@ +use std::collections::VecDeque; +use std::fs; + +use itertools::Itertools; + +fn to_grid(lines: Vec<&str>) -> Vec> { + let mut grid: Vec> = Vec::new(); + + for line in lines { + let mut row = Vec::new(); + for ch in line.chars() { + row.push(ch); + } + grid.push(row); + } + + grid +} + +fn find_goals(grid: &Vec>) -> Vec<(usize, usize)> { + let mut result = Vec::new(); + + // The goal locations are represented by digits in the grid + for (y, row) in grid.iter().enumerate() { + for (x, ch) in row.iter().enumerate() { + if ch.is_ascii_digit() { + result.push((x, y)); + } + } + } + + result +} + +fn goal_distances(grid: &Vec>, goals: &Vec<(usize, usize)>) -> Vec> { + let mut dists = Vec::new(); + for _i in 0..goals.len() { + dists.push([0].repeat(goals.len())); + } + + // For each goal location, find the distance to each other goal + for (i, &g) in goals.iter().enumerate() { + let mut visited = vec![g]; + let mut queue = VecDeque::from([(g, 0)]); + + // Do a breadth-first search to find the shortest paths + while queue.len() > 0 { + let (loc, depth) = queue.pop_front().unwrap(); + + // Have we reached another goal? If so, which one? + let oj = goals.iter().position(|&xy| xy == loc); + if oj.is_some() { + let j = oj.unwrap(); + dists[i][j] = depth; + } + + // Which adjacent locations are accessible? + let mut adjs = Vec::new(); + let u = (loc.0, loc.1 - 1); // up + let d = (loc.0, loc.1 + 1); // down + let l = (loc.0 - 1, loc.1); // left + let r = (loc.0 + 1, loc.1); // right + if grid[u.1][u.0] != '#' { + adjs.push(u); + } + if grid[d.1][d.0] != '#' { + adjs.push(d); + } + if grid[l.1][l.0] != '#' { + adjs.push(l); + } + if grid[r.1][r.0] != '#' { + adjs.push(r); + } + + // Standard breadth-first search stuff + for adj in adjs { + if !visited.contains(&adj) { + visited.push(adj); + queue.push_back((adj, depth + 1)); + } + } + } + } + + dists +} + +fn solve_puzzle(grid: &Vec>, go_back: bool) -> usize { + let goals = find_goals(&grid); + let dists = goal_distances(&grid, &goals); + + // This is the travelling salesman problem, so we must try all paths. + // We just brute-force the total distance for every order of the goals, + // and only keep the result if the path started at "0" as it should. + let mut shortest = 13371337; + for p in (0..goals.len()).permutations(goals.len()) { + let mut total = 0; + for i in 1..p.len() { + total += dists[p[i - 1]][p[i]]; + } + // Part 2: go back to the start too + if go_back { + total += dists[p[p.len() - 1]][p[0]]; + } + + // Is this the shortest path we've seen that start at "0"? + let first = goals[p[0]]; + if grid[first.1][first.0] == '0' && total < shortest { + shortest = total; + } + } + + shortest +} + +fn main() { + // Read layout from input text file + let input = fs::read_to_string("input.txt").unwrap(); + let lines = input.lines().collect(); + let grid = to_grid(lines); + + // Part 1 gives 430 for me + println!("Part 1 solution: {}", solve_puzzle(&grid, false)); + + // Part 2 gives 700 for me + println!("Part 2 solution: {}", solve_puzzle(&grid, true)); +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn part1_example1() { + let lines = vec![ + "###########", + "#0.1.....2#", + "#.#######.#", + "#4.......3#", + "###########", + ]; + let grid = to_grid(lines); + assert_eq!(solve_puzzle(&grid, false), 14); + } +} -- cgit v1.2.3