day12 task 1

Cargo.lock

@@ -1,10 +1,19 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "aho-corasick"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "aoc_2019"
 version = "0.1.0"
 dependencies = [
  "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -20,6 +29,46 @@ dependencies = [
  "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "memchr"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "regex"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "thread_local"
+version = "0.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [metadata]
+"checksum aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)" = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d"
 "checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
 "checksum itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f56a2d0bc861f9165be4eb3442afd3c236d8a98afd426f65d92324ae1091a484"
+"checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+"checksum memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88579771288728879b57485cc7d6b07d648c9f0141eb955f8ab7f9d45394468e"
+"checksum regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dc220bd33bdce8f093101afe22a037b8eb0e5af33592e6a9caafff0d4cb81cbd"
+"checksum regex-syntax 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)" = "11a7e20d1cce64ef2fed88b66d347f88bd9babb82845b2b858f3edbf59a4f716"
+"checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"

Cargo.toml

@@ -8,3 +8,4 @@ edition = "2018"
 
 [dependencies]
 itertools = "0.8.2"
+regex = "1.3.1"

input/day12.txt

@@ -0,0 +1,4 @@
+<x=19, y=-10, z=7>
+<x=1, y=2, z=-3>
+<x=14, y=-4, z=1>
+<x=8, y=7, z=-6>

src/main.rs

@@ -1,5 +1,5 @@
 mod tasks;
 
 fn main() {
-    tasks::day11::run();
+    tasks::day12::run();
 }

src/tasks/day12.rs

@@ -0,0 +1,101 @@
+use regex::Regex;
+
+#[allow(dead_code)]
+pub fn run() {
+    let regex = Regex::new("<x=(-?\\d+),\\sy=(-?\\d+),\\sz=(-?\\d+)").unwrap();
+    let input: Vec<Point> = std::fs::read_to_string("input/day12.txt")
+        .unwrap()
+        .lines()
+        .map(|line| {
+            let m = regex.captures(&line).unwrap();
+            let x: i32 = m[1].parse().unwrap();
+            let y: i32 = m[2].parse().unwrap();
+            let z: i32 = m[3].parse().unwrap();
+            Point { x, y, z }
+        })
+        .collect();
+    task1(input.clone());
+}
+
+fn task1(input: Vec<Point>) {
+    let moons: Vec<_> = input
+        .into_iter()
+        .map(|pos| Moon {
+            pos: pos,
+            vel: Point::new(0, 0, 0),
+        })
+        .collect();
+    let finals = (0..1000).fold(moons, |moons, _run| {
+        let gravities: Vec<Point> = moons
+            .iter()
+            .map(|base| {
+                moons.iter().fold(Point::new(0, 0, 0), |grav, other_moon| {
+                    grav.add(base.pos.gravity(other_moon.pos))
+                })
+            })
+            .collect();
+        let moons = moons
+            .into_iter()
+            .zip(gravities.into_iter())
+            .map(|(mut moon, grav)| {
+                moon.vel = moon.vel.add(grav);
+                moon.pos = moon.pos.add(moon.vel);
+                moon
+            })
+            .collect();
+        //println!("{}: {:?}", run, moons);
+        moons
+    });
+    let energy: i32 = finals
+        .iter()
+        .map(|moon| moon.pos.energy() * moon.vel.energy())
+        .sum();
+    println!("Task 1: sum of energy is {}", energy);
+    //392 too low
+}
+
+#[derive(Debug)]
+struct Moon {
+    pos: Point,
+    vel: Point,
+}
+
+#[derive(Clone, Copy, Debug)]
+struct Point {
+    x: i32,
+    y: i32,
+    z: i32,
+}
+
+impl Point {
+    fn new(x: i32, y: i32, z: i32) -> Self {
+        Point { x, y, z }
+    }
+
+    fn add(&self, other: Self) -> Self {
+        Point {
+            x: self.x + other.x,
+            y: self.y + other.y,
+            z: self.z + other.z,
+        }
+    }
+    fn gravity(&self, other: Self) -> Self {
+        fn d(a: i32, b: i32) -> i32 {
+            use std::cmp::Ordering;
+            match a.cmp(&b) {
+                Ordering::Less => 1,
+                Ordering::Equal => 0,
+                Ordering::Greater => -1,
+            }
+        }
+        Point {
+            x: d(self.x, other.x),
+            y: d(self.y, other.y),
+            z: d(self.z, other.z),
+        }
+    }
+
+    fn energy(&self) -> i32 {
+        self.x.abs() + self.y.abs() + self.z.abs()
+    }
+}

src/tasks/mod.rs

@@ -8,3 +8,4 @@ pub mod day08;
 pub mod day09;
 pub mod day10;
 pub mod day11;
+pub mod day12;