day 12 part 2 look for corners by two blueprints

newday.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# Check if the correct number of arguments is provided
+if [ "$#" -ne 1 ]; then
+    echo "Usage: $0 <two_digit_number>"
+    exit 1
+fi
+
+# Get the parameters
+X="$1"
+
+# Validate that X is a two-digit number
+if ! [[ "$X" =~ ^[0-9]{2}$ ]]; then
+    echo "Error: The parameter must be a two-digit number."
+    exit 1
+fi
+
+cp src/template.rs src/day$X.rs
+git add src/day$X.rs
+touch input/day$X.txt
+
+# Define the placeholder you want to replace
+PLACEHOLDER="{{day}}"
+
+# Use sed to replace the placeholder with the desired text
+sed -i "s|$PLACEHOLDER|$X|g" "src/day$X.rs"
+sed -i "s/.*\/\/ PLACEHOLDER.*/pub mod day$X;\n\/\/ PLACEHOLDER/" "src/lib.rs"
+sed -i "s/.*\/\/ PLACEHOLDER.*/($X, day$X::day_main),\n\/\/ PLACEHOLDER/" "src/main.rs"
+
+cargo fmt
+
+echo "seems allright. created template for day $X"

src/day10.rs

@@ -0,0 +1,141 @@
+use std::{
+    collections::{HashMap, HashSet},
+    fs::read_to_string,
+};
+
+use itertools::Itertools;
+
+use crate::utils::grid::Grid;
+
+pub fn day_main() {
+    let input = read_to_string("input/day10.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input)); // 832 wrong
+    println!(" part2: {}", part2(input));
+}
+
+type RiddleResult = usize;
+
+fn part1(input: &str) -> RiddleResult {
+    solve(input, true)
+}
+
+fn solve(input: &str, visit_once: bool) -> usize {
+    let grid = Grid::parse(input);
+    let m: HashMap<(i64, i64), u32> = HashMap::from_iter(grid.entries().map(|((x, y), c)| {
+        (
+            (x, y),
+            if *c == '.' {
+                1000
+            } else {
+                c.to_digit(10).unwrap()
+            },
+        )
+    }));
+    let grid = Grid::from(m);
+    let trail_heads = grid.entries().filter(|(_, h)| **h == 0).collect_vec();
+    let mut result = 0;
+    for (th, th_height) in trail_heads {
+        let mut count = 0;
+        let mut visited = HashSet::new();
+        let mut queue = vec![(th, th_height)];
+        while let Some((p, h)) = queue.pop() {
+            if visit_once && visited.contains(&(p, h)) {
+                continue;
+            }
+            visited.insert((p, h));
+
+            if *h == 9 {
+                count += 1;
+                continue;
+            }
+
+            let nexts = vec![
+                (p.0, p.1 + 1),
+                (p.0, p.1 - 1),
+                (p.0 + 1, p.1),
+                (p.0 - 1, p.1),
+            ];
+
+            for next in nexts {
+                if let Some(nh) = grid.get(next) {
+                    if *nh == h + 1 {
+                        queue.push((next, nh));
+                    }
+                }
+            }
+        }
+        result += count;
+    }
+    result
+}
+
+fn part2(input: &str) -> RiddleResult {
+    solve(input, false)
+}
+
+#[cfg(test)]
+mod test {
+    use super::{part1, part2};
+
+    const TEST_INPUT: &str = r"89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732";
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1(TEST_INPUT), 36);
+    }
+    #[test]
+    fn test1a() {
+        assert_eq!(
+            part1(
+                r"0123
+1234
+8765
+9876
+"
+            ),
+            1
+        );
+    }
+
+    #[test]
+    fn test1b() {
+        assert_eq!(
+            part1(
+                r"...0...
+...1...
+...2...
+6543456
+7.....7
+8.....8
+9.....9
+"
+            ),
+            2
+        );
+    }
+
+    #[test]
+    fn test2() {
+        assert_eq!(
+            part2(
+                r".....0.
+..4321.
+..5..2.
+..6543.
+..7..4.
+..8765.
+..9....
+"
+            ),
+            3
+        );
+    }
+}

src/day11.rs

@@ -0,0 +1,56 @@
+use std::{collections::HashMap, fs::read_to_string};
+
+pub fn day_main() {
+    let input = read_to_string("input/day11.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input));
+    println!(" part2: {}", part2(input));
+}
+
+type RiddleResult = usize;
+
+fn part1(input: &str) -> RiddleResult {
+    solve(input, 25)
+}
+
+fn solve(input: &str, blinks: i32) -> usize {
+    let mut stones: HashMap<usize, usize> =
+        input.split(" ").map(|v| (v.parse().unwrap(), 1)).collect();
+    let mut next = HashMap::new();
+    for _ in 0..blinks {
+        for (k, v) in stones {
+            if k == 0 {
+                next.entry(1).and_modify(|count| *count += v).or_insert(v);
+            } else if (k.ilog10() + 1) % 2 == 0 {
+                let l = (k.ilog10() + 1) / 2;
+                let z: usize = 10usize.pow(l);
+                let a = k / z;
+                let b = k % z;
+                next.entry(a).and_modify(|count| *count += v).or_insert(v);
+                next.entry(b).and_modify(|count| *count += v).or_insert(v);
+            } else {
+                let k_new = k * 2024;
+                next.entry(k_new)
+                    .and_modify(|count| *count += v)
+                    .or_insert(v);
+            }
+        }
+        stones = next;
+        next = HashMap::new();
+    }
+    stones.values().to_owned().sum()
+}
+
+fn part2(input: &str) -> RiddleResult {
+    solve(input, 75)
+}
+
+#[cfg(test)]
+mod test {
+    use super::part1;
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1("125 17"), 55312);
+    }
+}

src/day12.rs

@@ -0,0 +1,113 @@
+use std::{collections::HashSet, fs::read_to_string};
+
+use itertools::Itertools;
+
+use crate::utils::grid::{Coord, Grid};
+
+pub fn day_main() {
+    let input = read_to_string("input/day12.txt").unwrap();
+    let input = input.trim();
+    println!(" part1: {}", part1(input));
+    println!(" part2: {}", part2(input));
+}
+
+type RiddleResult = u64;
+
+const NEIGHBORS: &[Coord] = &[(1, 0), (0, 1), (-1, 0), (0, -1)];
+
+fn part1(input: &str) -> RiddleResult {
+    let garden = Grid::parse(input);
+    let mut processed: HashSet<Coord> = HashSet::new();
+    let mut result = 0;
+    for (p, c) in garden.entries() {
+        if processed.contains(&p) {
+            continue;
+        }
+        let mut area = 0;
+        let mut fence = 0;
+        let mut further = vec![p];
+        while let Some(current) = further.pop() {
+            if processed.contains(&current) {
+                continue;
+            }
+            area += 1;
+            for next in NEIGHBORS.iter().map(|d| (current.0 + d.0, current.1 + d.1)) {
+                let next_c = garden.get(next);
+                if next_c.is_none() || next_c.unwrap() != c {
+                    fence += 1;
+                } else {
+                    further.push(next);
+                }
+            }
+            processed.insert(current);
+        }
+        result += area * fence;
+    }
+    result
+}
+
+fn part2(input: &str) -> RiddleResult {
+    let garden = Grid::parse(input);
+    let mut processed: HashSet<Coord> = HashSet::new();
+    let mut result = 0;
+    for (p, c) in garden.entries() {
+        if processed.contains(&p) {
+            continue;
+        }
+        let mut area = 0;
+        let mut further = vec![p];
+        let mut convex_corners = 0;
+        let mut concave_corners = 0;
+        while let Some(current) = further.pop() {
+            if processed.contains(&current) {
+                continue;
+            }
+            area += 1;
+            for next in NEIGHBORS.iter().map(|d| (current.0 + d.0, current.1 + d.1)) {
+                let next_c = garden.get(next);
+                if next_c.is_none() || next_c.unwrap() != c {
+                } else {
+                    further.push(next);
+                }
+            }
+            processed.insert(current);
+            for (da, db) in NEIGHBORS.iter().circular_tuple_windows() {
+                let a = (current.0 + da.0, current.1 + da.1);
+                let b = (current.0 + db.0, current.1 + db.1);
+                if garden.get(a) != Some(c) && garden.get(b) != Some(c) {
+                    convex_corners += 1;
+                } else if garden.get(a) == Some(c)
+                    && garden.get(b) == Some(c)
+                    && garden.get((current.0 + da.0 + db.0, current.1 + da.1 + db.1)) != Some(c)
+                {
+                    concave_corners += 1;
+                }
+            }
+        }
+        let var_name = convex_corners + concave_corners;
+        let var_name = area * (var_name);
+        result += var_name;
+    }
+    result
+}
+
+#[cfg(test)]
+mod test {
+    use super::{part1, part2};
+
+    const TEST_INPUT: &str = r"AAAA
+BBCD
+BBCC
+EEEC
+";
+
+    #[test]
+    fn test1() {
+        assert_eq!(part1(TEST_INPUT), 140);
+    }
+
+    #[test]
+    fn test2() {
+        assert_eq!(part2(TEST_INPUT), 80);
+    }
+}

src/lib.rs

@@ -7,4 +7,8 @@ pub mod day06;
 pub mod day07;
 pub mod day08;
 pub mod day09;
+pub mod day10;
+pub mod day11;
+pub mod day12;
+// PLACEHOLDER
 pub mod utils;

src/main.rs

@@ -14,6 +14,10 @@ fn main() {
         (7, day07::day_main),
         (8, day08::day_main),
         (9, day09::day_main),
+        (10, day10::day_main),
+        (11, day11::day_main),
+        (12, day12::day_main),
+        // PLACEHOLDER
     ]);
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());
     let Some(day) = day else {

src/template.rs

@@ -1,7 +1,7 @@
 use std::fs::read_to_string;
 
 pub fn day_main() {
-    let input = read_to_string("input/dayXX.txt").unwrap();
+    let input = read_to_string("input/day{{day}}.txt").unwrap();
     let input = input.trim();
     println!(" part1: {}", part1(input));
     println!(" part2: {}", part2(input));

src/utils/grid.rs

@@ -3,11 +3,13 @@ use std::{
     ops::{Index, IndexMut},
 };
 
+use itertools::Itertools;
+
 /// A grid structure, indexed by (x, y) tuples. The top-left coordinate is (0, 0).
-#[derive(Eq, PartialEq, Debug)]
+#[derive(Eq, PartialEq, Debug, Clone)]
 pub struct Grid<T> {
-    content_width: i64,
-    content_height: i64,
+    pub content_width: i64,
+    pub content_height: i64,
     content: Vec<T>,
 }
 
@@ -36,10 +38,19 @@ impl<T> Grid<T> {
     }
 
     fn index_of(&self, c: Coord) -> usize {
+        if !self.contains_key(c) {
+            panic!(
+                "point {c:?} out of range (width: {}, height: {})",
+                self.content_width, self.content_height
+            );
+        }
         (c.1 * self.content_width + c.0) as usize
     }
 
     pub fn get(&self, c: Coord) -> Option<&T> {
+        if !self.contains_key(c) {
+            return None;
+        }
         let index = self.index_of(c);
         if index < self.content.len() {
             Some(&self.content[self.index_of(c)])
@@ -49,6 +60,9 @@ impl<T> Grid<T> {
     }
 
     pub fn get_mut(&mut self, c: Coord) -> Option<&mut T> {
+        if !self.contains_key(c) {
+            return None;
+        }
         let index = self.index_of(c);
         if index < self.content.len() {
             Some(&mut self.content[index])
@@ -73,7 +87,15 @@ impl<T> Grid<T> {
                 val,
             )
         })
-        // .collect_vec()
+    }
+
+    pub fn map_values<U>(self, f: fn(T) -> U) -> Grid<U> {
+        let new_content = self.content.into_iter().map(f).collect_vec();
+        Grid {
+            content_width: self.content_width,
+            content_height: self.content_height,
+            content: new_content,
+        }
     }
 }
 
@@ -179,10 +201,16 @@ mod test {
 
     #[should_panic]
     #[test]
-    fn out_of_bounds_panics() {
+    fn out_of_bounds_panics1() {
         generate()[(-1, 3)];
     }
 
+    #[should_panic]
+    #[test]
+    fn out_of_bounds_panics2() {
+        generate()[(1, 3)];
+    }
+
     #[test]
     fn option_success() {
         assert_eq!(Some(&'.'), generate().get((0, 0)));
@@ -192,4 +220,11 @@ mod test {
     fn option_out_of_bounds() {
         assert_eq!(None, generate().get((30, 0)));
     }
+
+    #[test]
+    fn value_mapping() {
+        let a: Grid<char> = generate();
+        let b: Grid<String> = a.map_values(|old| format!("{old}string"));
+        assert_eq!(".string".to_string(), b[(0, 0)]);
+    }
 }