Implement 2025 - Day 8 - Part 1

2025/08.rs

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+---cargo
+[dependencies]
+slotmap = "1"
+---
+
+use slotmap::SlotMap;
+use std::collections::HashMap;
+
+static CONTENT: &'static str = include_str!("./inputs/08_1.txt");
+
+fn main() {
+    let boxes: Vec<(usize, usize, usize)> = CONTENT.lines().map(|l| l.trim()).filter(|l| !l.is_empty()).map(|l| {
+        let (first, rest) = l.split_once(',').unwrap();
+        let (second, third) = rest.split_once(',').unwrap();
+
+        let first = first.parse::<usize>().unwrap();
+        let second = second.parse::<usize>().unwrap();
+        let third = third.parse::<usize>().unwrap();
+
+        (first, second, third)
+    }).collect();
+
+    let mut circuits = SlotMap::<_, Vec<(usize, usize, usize)>>::new();
+    let mut box_circuits = HashMap::<(usize, usize, usize), slotmap::DefaultKey>::new();
+
+    println!("Boxes\n{:?}", boxes);
+
+    let mut distances: Vec<_> = boxes.iter()
+        .flat_map(|s| core::iter::repeat(s).zip(boxes.iter()))
+        .filter(|(s, t)| s != t)
+        .filter(|(s, t)| ((s.0.pow(2) + s.1.pow(2) + s.2.pow(2)) as f64).sqrt() < ((t.0.pow(2) + t.1.pow(2) + t.2.pow(2)) as f64).sqrt())
+        .map(|(s, t)| (s, t, ((s.0.abs_diff(t.0).pow(2) + s.1.abs_diff(t.1).pow(2) + s.2.abs_diff(t.2).pow(2)) as f64).sqrt()))
+        .collect();
+    distances.sort_by(|(_, _, d1), (_, _, d2)| d2.partial_cmp(d1).unwrap());
+
+    // println!("Distances\n{:#?}", distances);
+
+    for _ in 0..1000 {
+        let (first, second, distance) = distances.pop().unwrap();
+        println!("Connecting:\n\t{:?} <=> {:?}", first, second);
+
+        let first_circuit = box_circuits.get(first);
+        let second_circuit = box_circuits.get(second);
+        println!("\tFirst Circuit:  {:?}", first_circuit);
+        println!("\tSecond Circuit: {:?}", second_circuit);
+
+        match (first_circuit.copied(), second_circuit.copied()) {
+            (Some(fc), Some(sc)) if fc == sc => {}
+            (Some(fc), Some(sc)) => {
+                let second_boxes = circuits.remove(sc).unwrap();
+                let first_boxes = circuits.get_mut(fc).unwrap();
+                for b in second_boxes {
+                    first_boxes.push(b);
+                    box_circuits.insert(b, fc);
+                }
+            },
+            (Some(fc), None) => {
+                circuits.get_mut(fc).unwrap().push(*second);
+                box_circuits.insert(*second, fc);
+            },
+            (None, Some(sc)) => {
+                circuits.get_mut(sc).unwrap().push(*first);
+                box_circuits.insert(*first, sc);
+            },
+            (None, None) => {
+                let circuit = circuits.insert(vec![*first, *second]);
+                box_circuits.insert(*first, circuit);
+                box_circuits.insert(*second, circuit);
+
+                println!("\tCreated Circuit: {:?}", circuit);
+            }
+        };
+    }
+
+    let mut circuit_list: Vec<_> = circuits.iter().map(|(k, v)| (k, v.len())).collect();
+    circuit_list.sort_by_key(|(_, v)| core::cmp::Reverse(*v));
+
+    println!("Circuits: {:?}", circuit_list);
+
+    let result = circuit_list.iter().take(3).map(|(_, v)| *v).product::<usize>();
+    println!("Result: {:?}", result);
+}

2025/inputs/08_example.txt

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+162,817,812
+57,618,57
+906,360,560
+592,479,940
+352,342,300
+466,668,158
+542,29,236
+431,825,988
+739,650,466
+52,470,668
+216,146,977
+819,987,18
+117,168,530
+805,96,715
+346,949,466
+970,615,88
+941,993,340
+862,61,35
+984,92,344
+425,690,689