Added Solution for 2023 day 11

2023/day11_cosmic_expansion/Cargo.toml

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+[package]
+name = "day11_cosmic_expansion"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+[dev-dependencies]
+criterion = "0.5.1"
+
+[[bench]]
+name = "test_benchmark"
+harness = false

2023/day11_cosmic_expansion/challenge.txt

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+You continue following signs for "Hot Springs" and eventually come across an [observatory](https://en.wikipedia.org/wiki/Observatory). The Elf within turns out to be a researcher studying cosmic expansion using the giant telescope here.
+
+He doesn't know anything about the missing machine parts; he's only visiting for this research project. However, he confirms that the hot springs are the next-closest area likely to have people; he'll even take you straight there once he's done with today's observation analysis.
+
+Maybe you can help him with the analysis to speed things up?
+
+The researcher has collected a bunch of data and compiled the data into a single giant *image* (your puzzle input). The image includes *empty space* (`.`) and *galaxies* (`#`). For example:
+
+```
+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....
+
+```
+
+The researcher is trying to figure out the sum of the lengths of the *shortest path between every pair of galaxies*. However, there's a catch: the universe expanded in the time it took the light from those galaxies to reach the observatory.
+
+Due to something involving gravitational effects, *only some space expands*. In fact, the result is that *any rows or columns that contain no galaxies* should all actually be twice as big.
+
+In the above example, three columns and two rows contain no galaxies:
+
+```
+   v  v  v
+ ...#......
+ .......#..
+ #.........
+>..........<
+ ......#...
+ .#........
+ .........#
+>..........<
+ .......#..
+ #...#.....
+   ^  ^  ^
+
+```
+
+These rows and columns need to be *twice as big*; the result of cosmic expansion therefore looks like this:
+
+```
+....#........
+.........#...
+#............
+.............
+.............
+........#....
+.#...........
+............#
+.............
+.............
+.........#...
+#....#.......
+
+```
+
+Equipped with this expanded universe, the shortest path between every pair of galaxies can be found. It can help to assign every galaxy a unique number:
+
+```
+....1........
+.........2...
+3............
+.............
+.............
+........4....
+.5...........
+............6
+.............
+.............
+.........7...
+8....9.......
+
+```
+
+In these 9 galaxies, there are *36 pairs*. Only count each pair once; order within the pair doesn't matter. For each pair, find any shortest path between the two galaxies using only steps that move up, down, left, or right exactly one `.` or `#` at a time. (The shortest path between two galaxies is allowed to pass through another galaxy.)
+
+For example, here is one of the shortest paths between galaxies `5` and `9`:
+
+```
+....1........
+.........2...
+3............
+.............
+.............
+........4....
+.5...........
+.##.........6
+..##.........
+...##........
+....##...7...
+8....9.......
+
+```
+
+This path has length `*9*` because it takes a minimum of *nine steps* to get from galaxy `5` to galaxy `9` (the eight locations marked `#` plus the step onto galaxy `9` itself). Here are some other example shortest path lengths:
+
+* Between galaxy `1` and galaxy `7`: 15
+* Between galaxy `3` and galaxy `6`: 17
+* Between galaxy `8` and galaxy `9`: 5
+
+In this example, after expanding the universe, the sum of the shortest path between all 36 pairs of galaxies is `*374*`.
+
+Expand the universe, then find the length of the shortest path between every pair of galaxies. *What is the sum of these lengths?*
+
+Your puzzle answer was `10228230`.
+
+\--- Part Two ---
+----------
+
+The galaxies are much *older* (and thus much *farther apart*) than the researcher initially estimated.
+
+Now, instead of the expansion you did before, make each empty row or column *one million times* larger. That is, each empty row should be replaced with `1000000` empty rows, and each empty column should be replaced with `1000000` empty columns.
+
+(In the example above, if each empty row or column were merely `10` times larger, the sum of the shortest paths between every pair of galaxies would be `*1030*`. If each empty row or column were merely `100` times larger, the sum of the shortest paths between every pair of galaxies would be `*8410*`. However, your universe will need to expand far beyond these values.)
+
+Starting with the same initial image, expand the universe according to these new rules, then find the length of the shortest path between every pair of galaxies. *What is the sum of these lengths?*
+
+Your puzzle answer was `447073334102`.
+
+Both parts of this puzzle are complete! They provide two gold stars: \*\*
+
+At this point, you should [return to your Advent calendar](/2023) and try another puzzle.
+
+If you still want to see it, you can [get your puzzle input](11/input).

2023/day11_cosmic_expansion/src/lib.rs

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+use core::fmt::Display;
+use std::num::ParseIntError;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum ParseError<'a> {
+    ParseIntError(std::num::ParseIntError),
+    LineMalformed(&'a str),
+}
+
+impl From<ParseIntError> for ParseError<'_> {
+    fn from(value: ParseIntError) -> Self {
+        Self::ParseIntError(value)
+    }
+}
+
+impl Display for ParseError<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::LineMalformed(v) => write!(f, "Line is malformed: {v}"),
+            Self::ParseIntError(e) => write!(f, "Unable to parse into integer: {e}"),
+        }
+    }
+}
+
+fn galaxies_from_image(input: &str, expansion: usize) -> Vec<(usize, usize)> {
+    let mut row = 0;
+    let mut galaxies = Vec::new();
+    input.lines().for_each(|line| {
+        let curr_line: Vec<_> = line.match_indices('#').collect();
+        if curr_line.is_empty() {
+            row += expansion;
+        } else {
+            curr_line.iter().for_each(|(col, _)| galaxies.push((row, *col)));
+            row += 1;
+        }
+    });
+    galaxies.sort_by(|a, b| b.1.cmp(&a.1));
+    (0..galaxies.len()-1).for_each(|idx| {
+        let diff = galaxies[idx].1 - galaxies[idx+1].1;
+        if diff > 1 {
+            galaxies.iter_mut().take(idx+1).for_each(|(_row, col)| *col += (diff-1)*expansion-1);
+        }
+    });
+    galaxies
+}
+
+pub fn run(input: &str) -> Result<(usize, usize), ParseError> {
+    let galaxies: Vec<_> = galaxies_from_image(input, 2);
+    let first = galaxies.iter().enumerate().map(|(idx, (y1, x1))| galaxies.iter().skip(idx+1).map(|(y2, x2)| y1.abs_diff(*y2) + x1.abs_diff(*x2)).sum::<usize>()).sum();
+    let galaxies: Vec<_> = galaxies_from_image(input, 1000000);
+    let second = galaxies.iter().enumerate().map(|(idx, (y1, x1))| galaxies.iter().skip(idx+1).map(|(y2, x2)| y1.abs_diff(*y2) + x1.abs_diff(*x2)).sum::<usize>()).sum();
+    Ok((first, second))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::read_to_string;
+
+    fn read_file(name: &str) -> String {
+        read_to_string(name).expect(&format!("Unable to read file: {name}")[..]).trim().to_string()
+    }
+
+    #[test]
+    fn test_sample() {
+        let sample_input = read_file("tests/sample_input");
+        assert_eq!(run(&sample_input), Ok((374, 82000210)));
+    }
+
+    #[test]
+    fn test_challenge() {
+        let challenge_input = read_file("tests/challenge_input");
+        assert_eq!(run(&challenge_input), Ok((10228230, 447073334102)));
+    }
+}

2023/day11_cosmic_expansion/tests/challenge_input

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+.....................................................................................#......#...............................................
+..#.....#.................................................................#........................#........................................
+...............................#...............................................................................#.....#......................
+.................................................#.............#...............................#...................................#........
+..............#......#.................#...............#............#.............#..........................................#..............
+.........................................................................................#.................#...............................#
+.#..........................................................................................................................................
+..........................#......#............................................#......#.................................#....................
+.................................................................................................#..........................................
+.........................................#..........#..........#............................................................#...............
+......#.....#......#..........................#........................#....................................................................
+....................................#.........................................................................#..........................#..
+..................................................................................#.........................................................
+...................................................................................................................#........................
+.................................................................#........................................#.................................
+.............................#..............................#..........................#.......#............................................
+..........................................#.....#.............................#.............................................................
+#..................#..................................................................................................................#.....
+....................................#...................#..........................#...........................#..............#.............
+........#................#...................#.............................................................................................#
+...............................#....................#...........................................#...........................................
+.......................................#..............................................#.....................................................
+........................................................................#........#...........................#..............................
+..................................#........#...................#........................................#.........#.................#.......
+#................#........................................................................................................#.................
+.........#.......................................#...............................................#.............................#........#...
+...............................................................................................................#............................
+.........................................................................................#..................................................
+...........................................................#..................................#..........#...........................#......
+......#.........................#..........................................................................................#................
+....................#.....................#.......#...............................#.................................#.......................
+..........................#..............................................#..................................................................
+..........#..........................#.......................#...................................#..............#..............#...........#
+......................................................#.....................................................................................
+............................................................................................................................................
+#...............................................#................#............................#.............................................
+..................#......................#............................#................................#................................#...
+............................................................................................................................................
+....................................................#....................................#.............................#....................
+..............#...................#................................#..........#..............................#.............................#
+............................#...............................................................................................#...............
+....#.................#.....................................#..........#............................................................#.......
+......................................................#.....................................................................................
+...........#..............................#.................................................#..........#.................#..................
+.................................#..............#................#..........#.......#.......................................................
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+........#.......#............................................................................................................#..............
+............................#.....................#..........#......................................#.....................................#.
+.....................................#.................................................#........................#...........................
+.........................................................................................................................#...........#......
+.......................#.............................#........................#.............................................................
+..............#...............................#.................#..................#........#...............................................
+...#......................................................................#.................................#..............................#
+...................#..................#.............................................................................#........#..............
+............................................................................................................................................
+.........................#.........................#........................................................................................
+......#......#.............................................#.............................#............#.....................................
+.................................#......................................#...................................................................
+.........................................#........................#..............................#.................#..............#.........
+............................................................................................................................................
+......................................................#.................................................#..............#..................#.
+......................#......#...............#...................................#............................#.............................
+....#...........#.................#............................................................#...............................#............
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+..........................................#................................................#...............................#............#...
+................................................................................................................#...........................
+..........#....................................#...................................................................................#........
+................................#....................#..............................................................#.......................
+......#.......................................................#...............................#.............................................
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+.................#...................#...........................................#..........................#...............................
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+..#........................................................................#....................................#.........#.................
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+......#.............................................................................................................#.....................#.
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+..............#...................#.........#...............................................................................................
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+.........#......................................................#...........................#...............................................
+.........................................#...................................#.................................#............................
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+................#...................................................................#.................#..................#..................
+.................................#..........................#.............#....................#................................#..........#
+...#........................#.........................................................................................................#.....
+.................................................#......................................#.....................#......#......................
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+........#......#...................................................................................................................#.....#..
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+..................................#.....#.................................#.................................................................
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+............................................................#...............................................................................
+.............................................#......................#..........#............#.........................#......#..............
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+.....................................................#..................#......................................#............................
+...#......................#.....................................................................................................#...........
+...........#...........................................................................#..............................................#.....
+................#..................................................#..............................................#.........................
+.......................#......................................................................#.............................................
+................................#........#.........#.....................#.....#......................#.....................................
+.#..........................................................................................................................................
+........................................................#................................#...................#..................#...........
+.....................................#........#.................................................#.......................................#...
+.........#...........#......................................................................................................................
+....................................................#.............................................................#.................#.......
+.............#............#........................................#.............#.....................#...................#...............#
+..................#....................#.................................#.............#....................................................
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+.......................#...............................................................................................#....................
+....#..........................................................#.....#..............#...........................................#...........
+...............................................................................................#..................#.......................#.
+.........#...................#............................................#.................................................................
+.............................................................................................................#..............#......#........
+...........................................................................................#................................................
+.#...........................................................#..............................................................................
+..............#..............................#........................................#.............#.......................................
+....................................#..............#..............#.........#.............................#.............#.............#.....
+....................#............................................................................................#..........................
+.........................................................................................#..................................................
+...........#............................#................#....................................................................#.............
+.....#......................................................................................................#...............................
+..................................#................................................#........#.............................................#.
+.#................#......#...........................................................................#......................................
+..............................................#.......................#................#............................................#.......
+.........#............................#........................#..........................................#.....#......#....................
+..............................................................................................#.............................................
+........................................................................................................................................#...
+..........................#........................#...............#................................#............................#..........
+..#........................................#............#............................................................#......................
+...............................#.....#........................................#.......#......................................#..............
+.......................................................................................................#....................................
+.....................................................#..............................................................................#.......
+........#......................................#...........................#.............................................#.................#
+...................#.....#......................................#.............................#.............................................
+............#.........................#......................................................................#.......#.................#....
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+............................................#.........................................................#.....................................
+.......#..........................#................#.....#.............#....................................................................
+..................#.........................................................#.............#.......................................#.........

2023/day11_cosmic_expansion/tests/sample_input

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+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....