From 818271e4ad11c968e930d74a3acbcf92264f079f Mon Sep 17 00:00:00 2001
From: Daniel Seiller <earthnuker@gmail.com>
Date: Thu, 17 Dec 2020 15:25:30 +0100
Subject: [PATCH] Day17 + formatting

---
 src/day15.rs   |  6 ++--
 src/day17p1.rs | 78 +++++++++++++++++++++++++++++++++++++++++++++++
 src/day17p2.rs | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs     |  2 ++
 4 files changed, 166 insertions(+), 3 deletions(-)
 create mode 100644 src/day17p1.rs
 create mode 100644 src/day17p2.rs

diff --git a/src/day15.rs b/src/day15.rs
index 9de00c6..d11c7d7 100644
--- a/src/day15.rs
+++ b/src/day15.rs
@@ -1,7 +1,7 @@
 use aoc_runner_derive::{aoc, aoc_generator};
 type Data = Vec<usize>;
 
-#[derive(Debug,Clone)]
+#[derive(Debug, Clone)]
 enum Seen {
     Never,
     Once(usize),
@@ -43,9 +43,9 @@ pub fn input_generator(input: &str) -> Data {
 }
 
 fn get_number(start: &[usize], num_turns: usize) -> usize {
-    let mut cache = vec![Seen::Never;num_turns];
+    let mut cache = vec![Seen::Never; num_turns];
     let mut nums = start.to_vec();
-    let mut num=std::usize::MAX;
+    let mut num = std::usize::MAX;
     for i in 1..num_turns {
         num = cache[nums[i - 1]].add(i);
         if i >= nums.len() {
diff --git a/src/day17p1.rs b/src/day17p1.rs
new file mode 100644
index 0000000..01bf411
--- /dev/null
+++ b/src/day17p1.rs
@@ -0,0 +1,78 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use std::collections::HashSet;
+
+#[derive(Clone)]
+pub struct Data {
+    active: HashSet<(i64, i64, i64)>,
+}
+
+impl Data {
+    pub fn count_neighbors(&self, x: i64, y: i64, z: i64) -> usize {
+        let mut ret = 0;
+        for dx in &[-1, 0, 1] {
+            for dy in &[-1, 0, 1] {
+                for dz in &[-1, 0, 1] {
+                    if (*dx == 0) && (*dy == 0) && (*dz == 0) {
+                        continue;
+                    }
+                    let is_active = self.active.contains(&(x + dx, y + dy, z + dz));
+                    if is_active {
+                        ret += 1;
+                    }
+                }
+            }
+        }
+        ret
+    }
+    pub fn update(&mut self) {
+        let mut checked = HashSet::new();
+        let mut next_active = HashSet::new();
+        for &(x, y, z) in &self.active {
+            for &dx in &[-1, 0, 1] {
+                for &dy in &[-1, 0, 1] {
+                    for &dz in &[-1, 0, 1] {
+                        let (nx, ny, nz) = (x + dx, y + dy, z + dz);
+                        if !checked.insert((nx, ny, nz)) {
+                            continue;
+                        }
+                        let nb = self.count_neighbors(nx, ny, nz);
+                        let is_active = self.active.contains(&(nx, ny, nz));
+                        if is_active && (nb == 2 || nb == 3) {
+                            next_active.insert((nx, ny, nz));
+                        } else if !is_active && nb == 3 {
+                            next_active.insert((nx, ny, nz));
+                        }
+                    }
+                }
+            }
+        }
+        self.active = next_active;
+    }
+
+    pub fn count(&self) -> usize {
+        return self.active.len();
+    }
+}
+
+#[aoc_generator(day17, part1)]
+pub fn input_generator(input: &str) -> Data {
+    let mut active = HashSet::new();
+    let z = 0;
+    for (y, line) in input.trim().lines().enumerate() {
+        for (x, c) in line.trim().chars().enumerate() {
+            if c == '#' {
+                active.insert((x as i64, y as i64, z as i64));
+            }
+        }
+    }
+    return Data { active };
+}
+
+#[aoc(day17, part1)]
+pub fn solve_part1(input: &Data) -> usize {
+    let mut data = input.clone();
+    for _ in 0..6 {
+        data.update()
+    }
+    return data.count();
+}
diff --git a/src/day17p2.rs b/src/day17p2.rs
new file mode 100644
index 0000000..80ba28d
--- /dev/null
+++ b/src/day17p2.rs
@@ -0,0 +1,83 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use std::collections::HashSet;
+
+#[derive(Clone)]
+pub struct Data {
+    active: HashSet<(i64, i64, i64, i64)>,
+}
+
+impl Data {
+    pub fn count_neighbors(&self, x: i64, y: i64, z: i64, w: i64) -> usize {
+        let mut ret = 0;
+        for dx in &[-1, 0, 1] {
+            for dy in &[-1, 0, 1] {
+                for dz in &[-1, 0, 1] {
+                    for dw in &[-1, 0, 1] {
+                        if (*dx == 0) && (*dy == 0) && (*dz == 0) && (*dw == 0) {
+                            continue;
+                        }
+                        let is_active = self.active.contains(&(x + dx, y + dy, z + dz, w + dw));
+                        if is_active {
+                            ret += 1;
+                        }
+                    }
+                }
+            }
+        }
+        ret
+    }
+    pub fn update(&mut self) {
+        let mut checked = HashSet::new();
+        let mut next_active = HashSet::new();
+        for &(x, y, z, w) in &self.active {
+            for &dx in &[-1, 0, 1] {
+                for &dy in &[-1, 0, 1] {
+                    for &dz in &[-1, 0, 1] {
+                        for &dw in &[-1, 0, 1] {
+                            let (nx, ny, nz, nw) = (x + dx, y + dy, z + dz, w + dw);
+                            if !checked.insert((nx, ny, nz, nw)) {
+                                continue;
+                            }
+                            let nb = self.count_neighbors(nx, ny, nz, nw);
+                            let is_active = self.active.contains(&(nx, ny, nz, nw));
+                            if is_active && (nb == 2 || nb == 3) {
+                                next_active.insert((nx, ny, nz, nw));
+                            } else if !is_active && nb == 3 {
+                                next_active.insert((nx, ny, nz, nw));
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        self.active = next_active;
+    }
+
+    pub fn count(&self) -> usize {
+        return self.active.len();
+    }
+}
+
+#[aoc_generator(day17, part2)]
+pub fn input_generator(input: &str) -> Data {
+    let mut active = HashSet::new();
+    let z = 0;
+    let w = 0;
+    for (y, line) in input.trim().lines().enumerate() {
+        for (x, c) in line.trim().chars().enumerate() {
+            if c == '#' {
+                active.insert((x as i64, y as i64, z as i64, w as i64));
+            }
+        }
+    }
+    return Data { active };
+}
+
+#[aoc(day17, part2)]
+pub fn solve_part1(input: &Data) -> usize {
+    let mut data = input.clone();
+    for _ in 0..6 {
+        data.update()
+    }
+    return data.count();
+}
diff --git a/src/lib.rs b/src/lib.rs
index 2b1429d..821a3fc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -15,4 +15,6 @@ pub mod day13;
 pub mod day14;
 pub mod day15;
 pub mod day16;
+pub mod day17p1;
+pub mod day17p2;
 aoc_lib! { year = 2020 }