update day3

src/day3.rs

@@ -0,0 +1,181 @@
+use std::collections::HashMap;
+
+use aoc_runner_derive::{aoc, aoc_generator};
+use array2d::Array2D;
+
+#[aoc_generator(day3)]
+fn parse(input: &str) -> Array2D<char> {
+    let rows: Vec<&str> = input.split("\n").collect();
+    let mut array = Vec::new();
+    for row in rows {
+        let row_vec: Vec<char> = row.chars().collect();
+        array.push(row_vec);
+    }
+
+    Array2D::from_rows(&array).unwrap()
+}
+
+#[aoc(day3, part1)]
+fn part1(array_2d: &Array2D<char>) -> u32 {
+    let mut r = 0;
+    for (y, row_iter) in array_2d.rows_iter().enumerate() {
+        let mut checked = false;
+        for (x, element) in row_iter.enumerate() {
+            let d: char = element.clone();
+            if d.is_digit(10) && !checked {
+                if !get_neighbors(x, y, &array_2d).is_empty() {
+                    checked = true;
+
+                    r += get_number(x, y, &array_2d)
+                }
+            } else if !d.is_digit(10) {
+                checked = false;
+            }
+        }
+    }
+
+    r
+}
+
+fn get_number(x: usize, y: usize, array2d: &Array2D<char>) -> u32 {
+    // We're dealing with only 3 digits numbers
+    let mut i = x.clone();
+    let mut j = x.clone() - 1;
+    let mut next_neighbors = Vec::new();
+    let mut prev_neighbors = Vec::new();
+    while array2d.get(y, i).is_some() && array2d.get(y, i).unwrap().is_digit(10) {
+        next_neighbors.push(array2d.get(y, i).unwrap());
+        i += 1
+    }
+    while array2d.get(y, j).is_some() && array2d.get(y, j).unwrap().is_digit(10) {
+        prev_neighbors.push(array2d.get(y, j).unwrap());
+        if j > 0 {
+            j -= 1
+        } else {
+            break;
+        }
+    }
+
+    let mut prev: Vec<&char> = prev_neighbors.clone().into_iter().rev().collect();
+    prev.append(&mut next_neighbors);
+
+    prev
+        .into_iter()
+        .fold(String::new(), |a, b| a + &b.to_string())
+        .parse()
+        .unwrap()
+}
+
+fn get_neighbors(x: usize, y: usize, array2d: &Array2D<char>) -> Vec<&char> {
+    let mut neighbors = Vec::new();
+    neighbors.push(array2d.get(y, x.checked_add(1).unwrap()));
+    if x > 0 {
+        neighbors.push(array2d.get(y, x.checked_sub(1).unwrap()));
+        neighbors.push(array2d.get(y.checked_add(1).unwrap(), x.checked_sub(1).unwrap()));
+    }
+    if y > 0 {
+        neighbors.push(array2d.get(y.checked_sub(1).unwrap(), x));
+        neighbors.push(array2d.get(y.checked_sub(1).unwrap(), x.checked_add(1).unwrap()));
+    }
+    if x > 0 && y > 0 {
+        neighbors.push(array2d.get(y.checked_sub(1).unwrap(), x.checked_sub(1).unwrap()));
+    }
+    neighbors.push(array2d.get(y.checked_add(1).unwrap(), x));
+    neighbors.push(array2d.get(y.checked_add(1).unwrap(), x.checked_add(1).unwrap()));
+
+    neighbors
+        .into_iter()
+        .flatten()
+        .filter(|c| !c.is_digit(10) && **c != '.')
+        .collect()
+}
+
+
+
+#[aoc(day3, part2)]
+fn part2(array_2d: &Array2D<char>) -> u32 {
+    // let mut r = Vec::new();
+    let mut stars_count: HashMap<(usize, usize), Vec<u32>> = HashMap::new();
+    for (y, row_iter) in array_2d.rows_iter().enumerate() {
+        let mut checked = false;
+        for (x, element) in row_iter.enumerate() {
+            let d: char = element.clone();
+            if d.is_digit(10) && !checked {
+                let star_vec = get_neighboring_star(x, y, &array_2d);
+                if !star_vec.is_empty() {
+                    let (x_star, y_star, _) = star_vec.first().unwrap().clone();
+                    let key = (x_star, y_star);
+                    let gear = get_number(x, y, &array_2d);
+                    if stars_count.contains_key(&key) {
+                        let mut v: Vec<u32> = stars_count.get(&(x_star, y_star)).unwrap().clone();
+                        v.push(gear);
+                        stars_count.insert(key, v);
+                    } else {
+                        stars_count.insert(key, vec![gear]);
+                    }
+                    checked = true
+                }
+            } else if !d.is_digit(10) {
+                checked = false;
+            }
+        }
+    }
+    let r = stars_count.iter().fold(0u32, |acc, (_, gears)| {
+        if gears.len() == 2 {
+            acc + gears.first().unwrap() * gears.last().unwrap()
+        } else {
+            acc
+        }
+    });
+
+    r
+}
+
+fn get_neighboring_star(x: usize, y: usize, array2d: &Array2D<char>) -> Vec<(usize, usize, Option<&char>)> {
+    let mut neighbors: Vec<(usize, usize, Option<&char>)> = Vec::new();
+    neighbors.push((x.checked_add(1).unwrap(), y, array2d.get(y, x.checked_add(1).unwrap())));
+    if x > 0 {
+        neighbors.push((x.checked_sub(1).unwrap(), y, array2d.get(y, x.checked_sub(1).unwrap())));
+        neighbors.push((x.checked_sub(1).unwrap(), y.checked_add(1).unwrap(), array2d.get(y.checked_add(1).unwrap(), x.checked_sub(1).unwrap())));
+    }
+    if y > 0 {
+        neighbors.push((x, y.checked_sub(1).unwrap(), array2d.get(y.checked_sub(1).unwrap(), x)));
+        neighbors.push((x.checked_add(1).unwrap(), y.checked_sub(1).unwrap(), array2d.get(y.checked_sub(1).unwrap(), x.checked_add(1).unwrap())));
+    }
+    if x > 0 && y > 0 {
+        neighbors.push((x.checked_sub(1).unwrap(), y.checked_sub(1).unwrap(), array2d.get(y.checked_sub(1).unwrap(), x.checked_sub(1).unwrap())));
+    }
+    neighbors.push((x, y.checked_add(1).unwrap(), array2d.get(y.checked_add(1).unwrap(), x)));
+    neighbors.push((x.checked_add(1).unwrap(), y.checked_add(1).unwrap(), array2d.get(y.checked_add(1).unwrap(), x.checked_add(1).unwrap())));
+
+    neighbors
+        .into_iter()
+        .filter(|(_, _, c)| c.is_some() && c.unwrap() == &'*')
+        .collect::<Vec<(usize, usize, Option<&char>)>>()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const EX: &str = r"467..114..
+...*......
+..35..633.
+......#...
+617*......
+.....+.58.
+..592.....
+......755.
+...$.*....
+.664.598..";
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(part1(&parse(EX)), 4361);
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(part2(&parse(EX)), 467835);
+    }
+}

src/lib.rs

@@ -1,3 +1,4 @@
+mod day3;
 mod day14;
 mod day13;
 mod day12;