Day 13, puzzle 2

src/bin/d13p2.rs

@@ -0,0 +1,24 @@
+use aoc22::{
+    day13::{self, Node},
+    util,
+};
+use itertools::Itertools;
+
+pub fn main() {
+    let mut pairs = day13::parse_pairs(&util::parse_input());
+    let mut packets = Vec::new();
+    while let Some(pair) = pairs.pop() {
+        packets.push(pair.0);
+        packets.push(pair.1);
+    }
+    let div1 = Node::List(vec![Node::List(vec![Node::Num(2)])]);
+    let div2 = Node::List(vec![Node::List(vec![Node::Num(6)])]);
+    packets.push(div1.clone());
+    packets.push(div2.clone());
+
+    packets.sort();
+    let n1 = packets.iter().find_position(|p| **p == div1).unwrap().0 + 1;
+    let n2 = packets.iter().find_position(|p| **p == div2).unwrap().0 + 1;
+
+    println!("Decoder key: {}", n1 * n2);
+}