From 5eec977c100c3372b34f970fd37bcfb14ff20551 Mon Sep 17 00:00:00 2001
From: Stefan Schwarz <stefan@f2o.io>
Date: Sun, 19 Apr 2020 12:32:18 +0200
Subject: [PATCH] yay solved day3-2

---
 src/day3/main.rs | 53 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 12 deletions(-)

diff --git a/src/day3/main.rs b/src/day3/main.rs
index 1d02f82..4e780a0 100644
--- a/src/day3/main.rs
+++ b/src/day3/main.rs
@@ -1,5 +1,6 @@
 use std::collections::HashSet;
 use std::io::{self, BufRead};
+use std::iter::FromIterator;
 
 #[derive(Debug)]
 enum Step {
@@ -10,7 +11,7 @@ enum Step {
 }
 
 impl Step {
-	fn draw(&self, map: &mut HashSet<Point>, start: &mut Point) {
+	fn draw(&self, map: &mut Vec<Point>, start: &mut Point) {
 		let mover: (i64, i64, &usize) = match self {
 			Step::Up(s) => (0, 1, s),
 			Step::Down(s) => (0, -1, s),
@@ -22,7 +23,7 @@ impl Step {
 		for _ in 0..*steps {
 			start.x += x;
 			start.y += y;
-			map.insert(start.clone());
+			map.push(start.clone());
 		}
 	}
 }
@@ -63,23 +64,51 @@ impl From<(i64, i64)> for Point {
 
 fn main() -> io::Result<()> {
 	let commands = load();
-	let mut wires: Vec<HashSet<Point>> = vec![];
+	let mut wires: Vec<Vec<Point>> = vec![];
 	commands.iter().enumerate().for_each(|(_, wire)| {
-		let mut map = HashSet::new();
+		let mut map = Vec::new();
 		let mut p: Point = (0, 0).into();
 		wire.iter().for_each(|step| {
 			step.draw(&mut map, &mut p);
 		});
 		wires.push(map);
 	});
-	let closest = wires[0].intersection(&wires[1]).fold(None, |min, point| {
-		let dist = point.dist_to_00();
-		match min {
-			None => Some(dist),
-			Some(min) => Some(if dist < min { dist } else { min }),
-		}
-	});
-	println!("closest: {}", closest.unwrap());
+	let wire_sets: Vec<HashSet<&Point>> = wires
+		.iter()
+		.map(|wire| HashSet::from_iter(wire.iter()))
+		.collect();
+	let closest = wire_sets[0]
+		.intersection(&wire_sets[1])
+		.fold(None, |min, point| {
+			let dist = point.dist_to_00();
+			match min {
+				None => Some(dist),
+				Some(min) => Some(if dist < min { dist } else { min }),
+			}
+		})
+		.expect("no mataching points found");
+	let shortest = wire_sets[0]
+		.intersection(&wire_sets[1])
+		.map(|point| {
+			wires[0].iter().position(|p| p == *point).unwrap()
+				+ wires[1].iter().position(|p| p == *point).unwrap()
+				+ 2
+		})
+		.fold(None, |min, dist| {
+			Some(match min {
+				None => dist,
+				Some(d) => {
+					if dist < d {
+						dist
+					} else {
+						d
+					}
+				}
+			})
+		})
+		.expect("no matching points found");
+	println!("closest: {}", closest);
+	println!("shortest: {}", shortest);
 	Ok(())
 }