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|
use std::{collections::VecDeque, num::ParseIntError, str::FromStr};
const STACK_ELEMENT_WIDTH: usize = 3;
const STACKS_SIZE: usize = 9;
#[derive(Debug, Clone)]
struct Stack {
stack: VecDeque<StackElement>,
}
impl FromStr for Stack {
type Err = ParseIntError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
Ok(Stack {
stack: s
.lines()
.map(|line| line.parse::<StackElement>().unwrap())
.collect::<VecDeque<_>>(),
})
}
}
impl Stack {
fn new() -> Self {
Stack {
stack: VecDeque::new(),
}
}
}
#[derive(Debug, Clone)]
struct StackElement {
ele: char,
}
impl FromStr for StackElement {
type Err = ParseIntError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let ch = s.chars().nth(1).unwrap();
Ok(StackElement { ele: ch })
}
}
#[derive(Debug)]
struct Command {
num_of_times: usize,
from: usize,
target: usize,
}
impl FromStr for Command {
type Err = ParseIntError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let s: Vec<usize> = s
.split_whitespace()
.collect::<Vec<_>>()
.iter()
.filter(|c| c.bytes().all(|c| c.is_ascii_digit()))
.map(|n| n.parse().unwrap())
.collect();
let (num_of_times, from, target) = (s[0], s[1], s[2]);
Ok(Command {
num_of_times,
from,
target,
})
}
}
fn apply_command(stacks: &mut Vec<Stack>, cmd: &Command, part1: bool) {
if part1 {
for _ in 0..cmd.num_of_times {
let element_to_push = stacks[cmd.from - 1]
.stack
.pop_back()
.expect("welp the stack is empty");
stacks[cmd.target - 1].stack.push_back(element_to_push);
}
} else {
let mut tmp_stack: VecDeque<StackElement> = VecDeque::new();
for _ in 0..cmd.num_of_times {
let element_to_push = stacks[cmd.from - 1]
.stack
.pop_back()
.expect("welp the stack is empty");
tmp_stack.push_back(element_to_push);
}
for _ in 0..cmd.num_of_times {
stacks[cmd.target - 1]
.stack
.push_back(tmp_stack.pop_back().unwrap());
}
}
}
fn solve_part_one(data: &str) -> String {
let mut stacks: Vec<Stack> = vec![Stack::new(); STACKS_SIZE];
let stack = data.split("\n\n").nth(0).unwrap();
for x in stack.lines() {
let chars = x.chars().clone();
for (i, ch) in x.chars().enumerate() {
if ch == '[' {
stacks[i / 4].stack.push_front(
chars.as_str()[i..i + STACK_ELEMENT_WIDTH]
.parse::<StackElement>()
.unwrap(),
)
}
}
}
let commands: Vec<Command> = data
.split("\n\n")
.nth(1)
.unwrap()
.lines()
.map(|command| command.parse::<Command>().unwrap())
.collect();
for cmd in &commands {
apply_command(&mut stacks, cmd, true);
}
let mut ans = "".to_string();
for i in 0..STACKS_SIZE {
if stacks[i].stack.len() >= 1 {
ans += stacks[i]
.stack
.iter()
.last()
.unwrap()
.ele
.to_string()
.as_str();
}
}
ans
}
fn solve_part_two(data: &str) -> String {
let mut stacks: Vec<Stack> = vec![Stack::new(); STACKS_SIZE];
let stack = data.split("\n\n").nth(0).unwrap();
for x in stack.lines() {
let chars = x.chars().clone();
for (i, ch) in x.chars().enumerate() {
if ch == '[' {
stacks[i / 4].stack.push_front(
chars.as_str()[i..i + STACK_ELEMENT_WIDTH]
.parse::<StackElement>()
.unwrap(),
)
}
}
}
let commands: Vec<Command> = data
.split("\n\n")
.nth(1)
.unwrap()
.lines()
.map(|command| command.parse::<Command>().unwrap())
.collect();
for cmd in &commands {
apply_command(&mut stacks, cmd, false);
}
let mut ans = "".to_string();
for i in 0..STACKS_SIZE {
if stacks[i].stack.len() >= 1 {
ans += stacks[i]
.stack
.iter()
.last()
.unwrap()
.ele
.to_string()
.as_str();
}
}
ans
}
fn main() {
let data_test = include_str!("../input/day5.test");
let data_prod = include_str!("../input/day5.prod");
println!("part one test: {}", solve_part_one(data_test));
println!("part one prod: {}", solve_part_one(data_prod));
println!("part two test: {}", solve_part_two(data_test));
println!("part two prod: {}", solve_part_two(data_prod));
}
|
