feat: upload day 8

Author: Nitestack

2024/day-8/Cargo.lock

@@ -0,0 +1,8 @@
+[package]
+name = "day-8"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+glam = "0.29.2"
+itertools = "0.14.0"

2024/day-8/Cargo.toml

@@ -0,0 +1,88 @@
+// ╭─────────────────────────────────────────────────────────╮
+// │ Advent of Code 2024 - Day 8                             │
+// ╰─────────────────────────────────────────────────────────╯
+
+use std::collections::HashSet;
+
+use glam::ivec2;
+
+use itertools::Itertools;
+
+fn main() {
+    let input = include_str!("../input.txt");
+    let frequencies = input
+        .lines()
+        .enumerate()
+        .flat_map(|(y, line)| {
+            line.chars()
+                .enumerate()
+                .filter(|(_, c)| *c != '.')
+                .map(|(x, c)| (c, ivec2(x as i32, y as i32)))
+                .collect::<Vec<_>>()
+        })
+        .into_group_map();
+    let height = input.lines().count() as i32;
+    let width = input.lines().next().unwrap().len() as i32;
+
+    // ── Part 1 ──────────────────────────────────────────────────────────
+    let anti_nodes_count = frequencies
+        .values()
+        .flat_map(|antennas| {
+            antennas.iter().flat_map(|first_pos| {
+                antennas
+                    .iter()
+                    .filter(|&second_pos| first_pos != second_pos)
+                    .filter_map(|second_pos| {
+                        let diff = second_pos - first_pos;
+                        let anti_node = second_pos + diff;
+                        if anti_node.x >= 0
+                            && anti_node.y >= 0
+                            && anti_node.x < width
+                            && anti_node.y < height
+                        {
+                            Some(anti_node)
+                        } else {
+                            None
+                        }
+                    })
+                    .collect::<Vec<_>>()
+            })
+        })
+        .collect::<HashSet<_>>()
+        .len();
+
+    println!("Antinodes count: {anti_nodes_count}");
+
+    // ── Part 2 ──────────────────────────────────────────────────────────
+    let anti_nodes_count = frequencies
+        .values()
+        .flat_map(|antennas| {
+            antennas.iter().flat_map(|first_pos| {
+                antennas
+                    .iter()
+                    .filter(|&second_pos| first_pos != second_pos)
+                    .flat_map(|second_pos| {
+                        let diff = second_pos - first_pos;
+                        let mut anti_nodes = vec![];
+                        for i in 1.. {
+                            let anti_node = first_pos + diff * i;
+                            if anti_node.x >= 0
+                                && anti_node.y >= 0
+                                && anti_node.x < width
+                                && anti_node.y < height
+                            {
+                                anti_nodes.push(anti_node)
+                            } else {
+                                break;
+                            }
+                        }
+                        anti_nodes
+                    })
+                    .collect::<Vec<_>>()
+            })
+        })
+        .collect::<HashSet<_>>()
+        .len();
+
+    println!("Antinodes count: {anti_nodes_count}");
+}