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46 lines
1.4 KiB
46 lines
1.4 KiB
use std::collections::HashMap;
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use aoc::input;
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fn main() {
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let chars = input::read_chars();
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// Part 1
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let mut houses = HashMap::<(i32, i32), u32>::new();
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let (mut x, mut y) = (0, 0);
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houses.insert((0, 0), 1);
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for c in chars.chars() {
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match c {
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'>' => x += 1,
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'<' => x -= 1,
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'v' => y += 1,
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'^' => y -= 1,
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_ => {}
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}
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let presents = houses.entry((x, y)).or_insert(0);
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*presents += 1;
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}
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let num_houses = houses.values().filter(|v| **v > 0).count();
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println!("Houses delivered: {}.", num_houses);
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// Part 2
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let mut houses = HashMap::<(i32, i32), u32>::new();
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let (mut x, mut y, mut rx, mut ry) = (0, 0, 0, 0);
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houses.insert((0, 0), 1);
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let mut is_robot_turn = false;
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for c in chars.chars() {
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match c {
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'>' => if is_robot_turn { rx += 1 } else { x += 1 },
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'<' => if is_robot_turn { rx -= 1 } else { x -= 1 },
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'v' => if is_robot_turn { ry += 1 } else { y += 1 },
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'^' => if is_robot_turn { ry -= 1 } else { y -= 1 },
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_ => {}
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}
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let presents = houses.entry(if is_robot_turn { (rx, ry) } else { (x, y) }).or_insert(0);
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*presents += 1;
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is_robot_turn = !is_robot_turn;
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}
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let num_houses = houses.values().filter(|v| **v > 0).count();
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println!("Houses delivered: {}.", num_houses);
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}
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