From 7b6e8f05e0be52d88309a547bbf832ebc6a0ac34 Mon Sep 17 00:00:00 2001
From: Sijmen Schoon <me@sijmenschoon.nl>
Date: Wed, 23 Dec 2020 02:38:29 +0100
Subject: [PATCH] rust(day17): Part 1

---
 rust/src/day17.rs | 99 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 rust/src/day17.rs

diff --git a/rust/src/day17.rs b/rust/src/day17.rs
new file mode 100644
index 0000000..eab4d68
--- /dev/null
+++ b/rust/src/day17.rs
@@ -0,0 +1,99 @@
+use std::time::{Duration, Instant};
+
+const SIZE: usize = 50;
+const OFFSET: usize = SIZE / 2;
+
+type Field = Vec<Vec<Vec<bool>>>;
+
+pub fn step(field: &mut Field) {
+    let mut changes = Vec::new();
+    for (z, slice) in field.iter().enumerate() {
+        for (y, row) in slice.iter().enumerate() {
+            for (x, cell) in row.iter().enumerate() {
+                let mut neighbors = 0;
+                for dz in -1..=1 {
+                    for dy in -1..=1 {
+                        for dx in -1..=1 {
+                            let nx = dx + x as i64;
+                            let ny = dy + y as i64;
+                            let nz = dz + z as i64;
+
+                            if (nx == x as i64 && ny == y as i64 && nz == z as i64)
+                                || (nx < 0 || nx >= SIZE as i64)
+                                || (ny < 0 || ny >= SIZE as i64)
+                                || (nz < 0 || nz >= SIZE as i64)
+                            {
+                                continue;
+                            }
+
+                            if field[nz as usize][ny as usize][nx as usize] {
+                                neighbors += 1;
+                            }
+                        }
+                    }
+                }
+
+                if *cell && neighbors != 2 && neighbors != 3 {
+                    changes.push((x, y, z, false));
+                }
+                if !cell && neighbors == 3 {
+                    changes.push((x, y, z, true));
+                }
+            }
+        }
+    }
+
+    for (x, y, z, state) in changes {
+        field[z][y][x] = state;
+    }
+}
+
+pub fn run(_: bool) -> Duration {
+    let input = std::fs::read_to_string("../inputs/17").unwrap();
+
+    let instant = Instant::now();
+
+    let mut field = vec![vec![vec![false; SIZE]; SIZE]; SIZE];
+    for (y, line) in input.lines().enumerate() {
+        for (x, cell) in line.chars().enumerate() {
+            field[OFFSET][y + OFFSET - 1][x + OFFSET - 1] = cell == '#';
+        }
+    }
+
+    // for y in 0..SIZE {
+    //     for x in 0..SIZE {
+    //         print!("{}", if field[OFFSET][y][x] { '#' } else { '.' });
+    //     }
+    //     println!();
+    // }
+
+    for i in 0..6 {
+        step(&mut field);
+
+        println!("step {}:", i + 1);
+        // for z in (OFFSET - 1)..=(OFFSET + 1) {
+        //     println!("z = {}", z as i64 - OFFSET as i64);
+        //     for y in 0..SIZE {
+        //         for x in 0..SIZE {
+        //             print!("{}", if field[z][y][x] { '#' } else { '.' });
+        //         }
+        //         println!();
+        //     }
+        //     println!();
+        // }
+    }
+
+    let mut alive = 0;
+    for slice in field {
+        for row in slice {
+            for cell in row {
+                if cell {
+                    alive += 1;
+                }
+            }
+        }
+    }
+    dbg!(alive);
+
+    instant.elapsed()
+}