2023-11: Implement part two

src/year_2023/day_11_cosmic_expantion/mod.rs

@@ -1,5 +1,5 @@
 pub mod part_one;
-//pub mod part_two;
+pub mod part_two;
 pub mod common;
 
 use crate::utils::solution::Solution;
@@ -19,7 +19,7 @@ impl Solution for DaySolution {
     }
 
     fn part_two(&self) -> String {
-        //input_reader::read_input_file(self.input_path, part_two::part_two)
-        String::from("Not implemented")
+        input_reader::read_input_file(self.input_path(), part_two::part_two)
+        //String::from("Not implemented")
     }
 }

src/year_2023/day_11_cosmic_expantion/part_two.rs

@@ -0,0 +1,77 @@
+use std::{collections::HashSet, usize};
+
+use super::common::{all_false, Galaxy};
+
+pub fn part_two(input_lines: Vec<String>) -> String {
+    let vert_dim = input_lines.len();
+    let horz_dim = input_lines[0].len();
+
+    let mut matrix = vec![vec![false; horz_dim]; vert_dim];
+    let mut galaxies: Vec<Galaxy> = Vec::new();
+
+    for (y, line) in input_lines.iter().enumerate() {
+        for (x, c) in line.chars().enumerate() {
+            matrix[y][x] = c == '#';            
+        }
+    }
+
+    let mut empty_rows_idx: HashSet<usize> = HashSet::new();
+    for i in 0..matrix.len() {
+        if all_false(&matrix[i]) {
+            empty_rows_idx.insert(i);
+        }
+    }
+
+    let mut emppty_cols_idx: HashSet<usize> = HashSet::new();
+    for i in 0..matrix[0].len() {
+        if all_false(&matrix.iter().map(|row| row[i]).collect::<Vec<bool>>()) {
+            emppty_cols_idx.insert(i);
+        }
+    }
+
+    for x in 0..matrix.len() {
+        for y in 0..matrix[x].len() {
+            if matrix[x][y] {
+                galaxies.push(Galaxy { i: x, j: y });
+            }
+        }
+    }
+    
+    let mut total_distance = 0;
+    for i in 0..(galaxies.len() - 1) {
+        total_distance += distances_from_galaxy(i, &galaxies, &empty_rows_idx, &emppty_cols_idx);
+    }
+
+    total_distance.to_string()
+}
+
+fn distances_from_galaxy(id : usize, galaxies: &Vec<Galaxy>, empty_rows_idx: &HashSet<usize>, emppty_cols_idx: &HashSet<usize>) -> usize {
+    let mut distance: usize = 0;
+    for i in (id + 1)..galaxies.len() {
+        distance += expanded_euclidian_distance(galaxies[id].i, galaxies[id].j, galaxies[i].i, galaxies[i].j, empty_rows_idx, emppty_cols_idx);
+    }
+    distance
+}
+
+fn expanded_euclidian_distance(x1: usize, y1: usize, x2: usize, y2: usize, empty_rows_idx: &HashSet<usize>, emppty_cols_idx: &HashSet<usize>) -> usize {
+    expand_distance(x1, x2, empty_rows_idx) + expand_distance(y1, y2, emppty_cols_idx)
+}
+
+fn expand_distance(a: usize, b: usize, empty_ids: &HashSet<usize>) -> usize {
+
+    if a > b {
+        return expand_distance(b, a, empty_ids);
+    }
+
+    let mut res = 0;
+
+    for i in a..b {
+        if empty_ids.contains(&i) {
+            res += 1000000;
+        } else {
+            res += 1;
+        }
+    }
+
+    res
+}