First commit for Rust work days 1&2

2016/day01/src/main.rs

@@ -1,3 +1,86 @@
-fn main() {
-    println!("Hello, world!");
+use std::io::Read;
+use std::fs::File;
+
+fn turn(state: &(i32, i32), direction: &String) -> (i32, i32) {
+    match direction.as_ref() {
+        "R" => { // clockwise motion
+            (-1 * state.1, 1 * state.0)
+        },
+        "L" => { //rotate widdershins
+            (1 * state.1, -1 * state.0)
+        },
+        _ => {
+            println!("Invalid direction: {}", direction);
+            (state.0, state.1)
+        },
+    }
 }
+
+fn step(state: &(i32, i32), pos: &(i32, i32), dist: i32) -> (i32, i32) {
+    (pos.0 + state.0 * dist, pos.1 + state.1 * dist)
+}
+
+// fn state_to_direction(state: &(i32, i32)) -> String {
+//     match state.0 {
+//         1 => "N",
+//         -1 => "S",
+//         0 => {
+//             match state.1 {
+//                 1 => "E",
+//                 -1 => "W",
+//                 _ => "Invalid",
+//             }
+//         },
+//         _ => "Invalid",
+//     }
+// }
+
+fn part_1(input: &String) {
+    let mut state = (1, 0);
+    let mut pos = (0, 0);
+    for item in input.trim().split(", ") {
+        let (dir, dist) = item.split_at(1);
+        let dir: String = dir.to_string();
+        let dist: i32 = dist.parse::<i32>().unwrap();
+
+        state = turn(&state, &dir);
+        pos = step(&state, &pos, dist);
+
+        //println!("Moved {} {} to arrive at ({}, {})", dist, dir, pos.0, pos.1);
+    }
+    println!("Part 1: Ended up at ({}, {}), {} away from the start", pos.0, pos.1, pos.0.abs() + pos.1.abs());
+}
+
+fn part_2(input: &String) {
+    let mut state = (1, 0);
+    let mut positions: Vec<(i32, i32)> = vec![(0, 0)];
+
+    for item in input.trim().split(", ") {
+        let (dir, dist) = item.split_at(1);
+        let dir: String = dir.to_string();
+        let dist: i32 = dist.parse::<i32>().unwrap();
+
+        state = turn(&state, &dir);
+        let pos = step(&state, positions.last().unwrap(), dist);
+        print!("Move {} {} to ({}, {}) - ", dist, dir, pos.0, pos.1);
+        match positions.iter().position(|&p| p == pos) {
+            Some(v) => {
+                println!("Part 2: Stopped twice at ({}, {}) on element {}, {} away from the start", pos.0, pos.1, v, pos.0.abs() + pos.1.abs());
+                break;
+            },
+            None => {
+                println!("Did not match {} locations", positions.len());
+                positions.push(pos);
+            },
+        }
+    }
+}
+
+fn main() {
+    let mut file = File::open("./data").expect("could not open file");
+    let mut input = String::new();
+    file.read_to_string(&mut input).expect("could not read file");
+
+    //part_1(&input);
+    part_2(&input);
+}