From df219182e87d28e19b74ef0b32143fb51a4bed02 Mon Sep 17 00:00:00 2001
From: Stefan Schwarz <stefan@f2o.io>
Date: Thu, 14 May 2020 23:35:15 +0200
Subject: [PATCH] day12

---
 Cargo.toml        |   6 ++-
 src/day12/main.rs | 122 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+), 1 deletion(-)
 create mode 100644 src/day12/main.rs

diff --git a/Cargo.toml b/Cargo.toml
index 3ee5431..719d289 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -36,4 +36,8 @@ path = "src/day9/main.rs"
 
 [[bin]]
 name = "day10"
-path = "src/day10/main.rs"
\ No newline at end of file
+path = "src/day10/main.rs"
+
+[[bin]]
+name = "day12"
+path = "src/day12/main.rs"
diff --git a/src/day12/main.rs b/src/day12/main.rs
new file mode 100644
index 0000000..1cef6c0
--- /dev/null
+++ b/src/day12/main.rs
@@ -0,0 +1,122 @@
+use std::cmp::Ordering;
+use std::iter::FromIterator;
+
+#[derive(PartialEq, Debug, Default)]
+struct Object {
+    x: isize,
+    y: isize,
+    z: isize,
+}
+
+impl From<(isize, isize, isize)> for Object {
+    fn from(o: (isize, isize, isize)) -> Self {
+        Object {
+            x: o.0,
+            y: o.1,
+            z: o.2,
+        }
+    }
+}
+
+impl Object {
+    fn attract(&self, other: &Object, v: &mut Object) {
+        v.x += Object::cmp(self.x, other.x);
+        v.y += Object::cmp(self.y, other.y);
+        v.z += Object::cmp(self.z, other.z);
+    }
+
+    fn apply(&mut self, v: &Object) {
+        self.x += v.x;
+        self.y += v.y;
+        self.z += v.z;
+    }
+
+    fn cmp(a: isize, b: isize) -> isize {
+        match b.cmp(&a) {
+            Ordering::Less => -1,
+            Ordering::Equal => 0,
+            Ordering::Greater => 1,
+        }
+    }
+
+    fn energy(&self) -> usize {
+        return (self.x.abs() + self.y.abs() + self.z.abs()) as usize;
+    }
+}
+
+struct Space {
+    moons: Vec<Object>,
+    velocy: Vec<Object>,
+}
+
+impl From<Vec<Object>> for Space {
+    fn from(moons: Vec<Object>) -> Self {
+        let velocy = Vec::from_iter((0..moons.len()).map(|_| Object::default()));
+        Space { moons, velocy }
+    }
+}
+
+impl Space {
+    fn step(&mut self) -> impl Iterator<Item = (&'_ Object, &'_ Object, usize)> {
+        let moons: &mut Vec<Object> = self.moons.as_mut();
+        let velocy: &mut Vec<Object> = self.velocy.as_mut();
+
+        moons.iter().enumerate().for_each(|(idx, a)| {
+            moons.iter().for_each(|b| {
+                if a == b {
+                    return;
+                }
+                a.attract(b, velocy.get_mut(idx).unwrap())
+            })
+        });
+        moons
+            .iter_mut()
+            .enumerate()
+            .for_each(|(idx, m)| m.apply(velocy.get(idx).unwrap()));
+        moons
+            .iter()
+            .zip(velocy.iter())
+            .map(|(a, b)| (a, b, a.energy() * b.energy()))
+    }
+}
+
+fn main() {
+    let moons = vec![
+        Object::from((-1, 0, 2)),
+        Object::from((2, -10, -7)),
+        Object::from((4, -8, 8)),
+        Object::from((3, 5, -1)),
+    ];
+    let moons = vec![
+        Object::from((-8, -10, 0)),
+        Object::from((5, 5, 10)),
+        Object::from((2, -7, 3)),
+        Object::from((9, -8, -3)),
+    ];
+    let moons = vec![
+        Object::from((17, 5, 1)),
+        Object::from((-2, -8, 8)),
+        Object::from((7, -6, 14)),
+        Object::from((1, -10, 4)),
+    ];
+    let mut space = Space::from(moons);
+
+    let mut total_energy = 0;
+    (1..=100).for_each(|_i| {
+        (1..=9).for_each(|_| {
+            space.step().count();
+        });
+        let step_energy = space
+            .step()
+            .map(|(o, v, e)| {
+                println!("{:?} {:?}", o, v);
+                e
+            })
+            .fold(0, |mut acc, c| {
+                acc += c;
+                acc
+            });
+        total_energy += step_energy;
+        println!("total:{}, stepe:{}", total_energy, step_energy)
+    })
+}