From 45589225f35c5fa8ac04705cafda535c04b4aaf2 Mon Sep 17 00:00:00 2001
From: Ben C <bwc9876@gmail.com>
Date: Mon, 8 Dec 2025 00:55:32 -0500
Subject: [PATCH] Day 8

---
 years/2025/src/day_8.rs             | 115 ++++++++++++++++++++++++++--
 years/2025/src/examples/day_8/1.txt |  21 +++++
 years/2025/src/examples/day_8/2.txt |  21 +++++
 3 files changed, 152 insertions(+), 5 deletions(-)

diff --git a/years/2025/src/day_8.rs b/years/2025/src/day_8.rs
index daae1dc..e68aea9 100644
--- a/years/2025/src/day_8.rs
+++ b/years/2025/src/day_8.rs
@@ -1,17 +1,122 @@
+use std::{collections::HashMap, ops::Sub};
 
 use advent_core::{Day, day_stuff, ex_for_day};
 
 pub struct Day8;
 
+#[derive(Debug, Clone, Copy, Eq, Hash, PartialEq)]
+pub struct Pos(isize, isize, isize);
+
+impl Sub for Pos {
+    type Output = isize;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        (self.0 - rhs.0).pow(2) + (self.1 - rhs.1).pow(2) + (self.2 - rhs.2).pow(2)
+    }
+}
+
 impl Day for Day8 {
+    day_stuff!(8, "40", "25272", (usize, Vec<Pos>));
+
+    fn part_1((amnt, input): Self::Input) -> Option<String> {
+        let mut circuits = input
+            .iter()
+            .enumerate()
+            .map(|(i, &p)| (p, i))
+            .collect::<HashMap<Pos, usize>>();
+
+        let mut distances = input
+            .iter()
+            .enumerate()
+            .flat_map(|(i, p)| input.iter().skip(i + 1).map(|&p2| (*p, p2, *p - p2)))
+            .collect::<Vec<_>>();
+
+        distances.sort_by_key(|(_, _, x)| *x);
+
+        for (p1, p2, _dist) in distances.into_iter().take(amnt) {
+            let target_circ = circuits.get(&p1).copied().unwrap();
+            let replace_circ = circuits.get(&p2).copied().unwrap();
+
+            if target_circ == replace_circ {
+                continue;
+            }
+
+            for (_p, v) in circuits.iter_mut().filter(|(_, v)| **v == replace_circ) {
+                *v = target_circ;
+            }
+        }
+
+        let mut counts = circuits
+            .into_iter()
+            .fold(HashMap::new(), |mut acc, (_, c)| {
+                *(acc.entry(c).or_insert(0)) += 1;
+                acc
+            })
+            .into_iter()
+            .map(|(_, count)| count)
+            .collect::<Vec<_>>();
+
+        counts.sort_by(|a, b| a.cmp(b).reverse());
 
-    day_stuff!(8, "", "");
+        Some(
+            counts
+                .into_iter()
+                .take(3)
+                .fold(1, |acc, x| acc * x)
+                .to_string(),
+        )
+    }
+
+    fn part_2((_amnt, input): Self::Input) -> Option<String> {
+        let mut circuits = input
+            .iter()
+            .enumerate()
+            .map(|(i, &p)| (p, i))
+            .collect::<HashMap<Pos, usize>>();
+
+        let mut distances = input
+            .iter()
+            .enumerate()
+            .flat_map(|(i, p)| input.iter().skip(i + 1).map(|&p2| (*p, p2, *p - p2)))
+            .collect::<Vec<_>>();
+
+        distances.sort_by_key(|(_, _, x)| *x);
+
+        let mut last_2: Option<(Pos, Pos)> = None;
+
+        for (p1, p2, _dist) in distances.into_iter() {
+            let target_circ = circuits.get(&p1).copied().unwrap();
+            let replace_circ = circuits.get(&p2).copied().unwrap();
+
+            if target_circ == replace_circ {
+                continue;
+            }
 
-    fn part_1(_input: Self::Input) -> Option<String> {
-        None
+            last_2 = Some((p1, p2));
+
+            for (_p, v) in circuits.iter_mut().filter(|(_, v)| **v == replace_circ) {
+                *v = target_circ;
+            }
+        }
+
+        let (a, b) = last_2.unwrap();
+
+        Some((a.0 * b.0).to_string())
     }
 
-    fn part_2(_input: Self::Input) -> Option<String> {
-        None
+    fn parse_input(input: &str) -> Self::Input {
+        let mut lines = input.lines();
+
+        let amnt = lines.next().unwrap().parse::<usize>().unwrap();
+
+        let poses = lines
+            .map(|l| {
+                let (x, r) = l.split_once(',').unwrap();
+                let (y, z) = r.split_once(',').unwrap();
+                Pos(x.parse().unwrap(), y.parse().unwrap(), z.parse().unwrap())
+            })
+            .collect();
+
+        (amnt, poses)
     }
 }
diff --git a/years/2025/src/examples/day_8/1.txt b/years/2025/src/examples/day_8/1.txt
index e69de29..907ced5 100644
--- a/years/2025/src/examples/day_8/1.txt
+++ b/years/2025/src/examples/day_8/1.txt
@@ -0,0 +1,21 @@
+10
+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
diff --git a/years/2025/src/examples/day_8/2.txt b/years/2025/src/examples/day_8/2.txt
index e69de29..907ced5 100644
--- a/years/2025/src/examples/day_8/2.txt
+++ b/years/2025/src/examples/day_8/2.txt
@@ -0,0 +1,21 @@
+10
+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
-- 
2.51.2