Add day 3 part 1 in Rust

2019/03/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "d3"
+version = "0.1.0"
+authors = ["kageru <kageru@encode.moe>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2019/03/src/main.rs

@@ -0,0 +1,56 @@
+use std::collections::{HashMap, HashSet};
+use std::io::{self, BufRead};
+
+struct Movement {
+    pub direction: char,
+    pub distance: u16,
+}
+
+impl Movement {
+    pub fn new(raw: &str) -> Self {
+        Self {
+            direction: raw.chars().nth(0).unwrap(),
+            distance: raw.get(1..).unwrap().parse().unwrap(),
+        }
+    }
+}
+
+fn make_step(x: &mut i32, y: &mut i32, dir: char) {
+    match dir {
+        'U' => *y += 1,
+        'D' => *y -= 1,
+        'L' => *x += 1,
+        _ => *x -= 1,
+    };
+}
+
+pub fn main() {
+    let stdin = io::stdin();
+    let mut input = stdin.lock().lines().map(|s| {
+        s.unwrap()
+            .split(',')
+            .map(|m| Movement::new(m))
+            .collect::<Vec<_>>()
+    });
+    let (first_wire, second_wire) = (input.next().unwrap(), input.next().unwrap());
+    let mut first_wire_positions = HashSet::new();
+    let (mut x, mut y) = (0, 0);
+    for m in first_wire {
+        for _ in 0..m.distance {
+            make_step(&mut x, &mut y, m.direction);
+            first_wire_positions.insert((x, y));
+        }
+    }
+    x = 0;
+    y = 0;
+    let mut intersections = HashMap::new();
+    for m in second_wire {
+        for _ in 0..m.distance {
+            make_step(&mut x, &mut y, m.direction);
+            if first_wire_positions.contains(&(x, y)) {
+                intersections.insert((x, y), 0);
+            }
+        }
+    }
+    println!("Part 1: {}", intersections.keys().map(|(x, y)| x.abs() + y.abs()).min().unwrap());
+}