118 lines
4.3 KiB
Rust
118 lines
4.3 KiB
Rust
// Santa's sleigh uses a very high-precision clock to guide its movements, and the clock's
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// oscillator is regulated by stars. Unfortunately, the stars have been stolen... by the Easter
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// Bunny. To save Christmas, Santa needs you to retrieve all fifty stars by December 25th.
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//
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// Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent
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// calendar; the second puzzle is unlocked when you complete the first. Each puzzle grants one
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// star. Good luck!
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//
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// You're airdropped near Easter Bunny Headquarters in a city somewhere. "Near", unfortunately, is
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// as close as you can get - the instructions on the Easter Bunny Recruiting Document the Elves
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// intercepted start here, and nobody had time to work them out further.
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//
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// The Document indicates that you should start at the given coordinates (where you just landed)
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// and face North. Then, follow the provided sequence: either turn left (L) or right (R) 90
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// degrees, then walk forward the given number of blocks, ending at a new intersection.
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//
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// There's no time to follow such ridiculous instructions on foot, though, so you take a moment
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// and work out the destination. Given that you can only walk on the street grid of the city,
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// how far is the shortest path to the destination?
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//
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// For example:
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//
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// Following R2, L3 leaves you 2 blocks East and 3 blocks North, or 5 blocks away.
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// R2, R2, R2 leaves you 2 blocks due South of your starting position, which is 2 blocks away.
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// R5, L5, R5, R3 leaves you 12 blocks away.
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// How many blocks away is Easter Bunny HQ?
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//
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use std::{env, fs};
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use aoc::read_data;
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use crate::CardinalDirection::*;
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#[derive(Debug)]
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enum CardinalDirection {
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North,
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South,
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East,
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West
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}
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fn manhattan_distance(directions: &str) -> i32 {
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let (mut x_distance, mut y_distance, mut x_move, mut y_move) = (0i32,0i32, 0i32, 0i32);
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let mut current_direction = North;
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for next_direction in directions.split(", ") {
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let (direction, vector) = next_direction.split_at(1);
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let distance = vector.parse().unwrap();
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// print!("[{}] At {x_distance}x{y_distance}, FACING {current_direction:?}, TURN {} MOVE {} ::::::", next_direction, direction, distance);
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x_move = 0; y_move = 0;
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match direction {
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"R" => {
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match current_direction {
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North => {
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current_direction = East;
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x_move = distance;
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}
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South => {
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current_direction = West;
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x_move = distance * -1 ;
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}
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East => {
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current_direction = South;
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y_move = distance * -1;
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}
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West => {
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current_direction = North;
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y_move = distance;
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}
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}
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}
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"L" => {
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match current_direction {
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North => {
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current_direction = West;
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x_move = distance * -1;
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}
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South => {
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current_direction = East;
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x_move = distance;
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}
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East => {
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current_direction = North;
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y_move = distance;
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}
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West => {
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current_direction = South;
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y_move = distance * -1;
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}
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}
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}
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_ => {
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println!("INVALID DIRECTION");
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}
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}
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x_distance += x_move;
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y_distance += y_move;
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// println!("facing {:?} at {}x{} (moved {}x{})", current_direction, x_distance, y_distance, x_move, y_move);
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}
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x_distance.abs() + y_distance.abs()
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}
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fn main() {
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let binding = read_data("2016_01_data.txt");
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let directions = binding.as_str();
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let parmas: Vec<(&str, i32)> = vec![
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("R2, L3", 5),
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("R2, R2, R2", 2),
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("R5, L5, R5, R3", 12),
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(directions, 252)];
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for (param, expected) in parmas {
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println!("Manhattan Distance of {} Expected {}", manhattan_distance(param) , expected);
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}
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}
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// 252
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