1 files changed, 47 insertions, 0 deletions
diff --git a/2018/src/bin/day_25.rs b/2018/src/bin/day_25.rs
new file mode 100644
index 0000000..9e74f49
--- /dev/null
+++ b/2018/src/bin/day_25.rs
@@ -0,0 +1,47 @@
+extern crate advent_of_code_2018;
+use advent_of_code_2018::*;
+
+use std::error::Error;
+use std::path::PathBuf;
+
+// cargo watch -cs "cargo run --release --bin day_25"
+
+fn main() -> Result<(), Box<Error>> {
+    let input = read_file(&PathBuf::from("inputs/25.txt"))?;
+
+    let mut constellations: Vec<Vec<Vec<i32>>> = input.iter()
+        .map(|line| line.split(',').map(|x| x.parse().unwrap()).collect::<Vec<_>>())
+        .map(|points| vec!(points))
+        .collect();
+
+    // debug!(constellations);
+
+    while join_constellations(&mut constellations) {
+    }
+
+    debug!(constellations.len());
+    
+    Ok(())
+}
+
+fn distance(xs: &[i32], ys: &[i32]) -> i32 {
+    xs.iter().zip(ys.iter()).map(|(x,y)| (x - y).abs()).sum()
+}
+
+fn join_constellations(constellations: &mut Vec<Vec<Vec<i32>>>) -> bool {
+    for i in 0..constellations.len()-1 {
+        for j in i+1..constellations.len() {
+            let connected = constellations[i].iter().any(|ci| {
+                constellations[j].iter().any(|cj| {
+                    distance(&ci, &cj) <= 3
+                })
+            });
+            if connected {
+                let mut to_join = constellations.remove(j);
+                constellations[i].append(&mut to_join);
+                return true;
+            }
+        }
+    }
+    false
+}