156 lines
4.1 KiB
Rust
156 lines
4.1 KiB
Rust
use crate::common::AdventOfCodeDay;
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pub struct Day18 {
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input: Vec<String>,
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}
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impl Day18 {
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pub fn new() -> Self {
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let input_bytes = include_bytes!("../res/18_input.txt");
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let input_str = String::from_utf8_lossy(input_bytes);
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let lines = input_str
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.lines()
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.map(|p| String::from(p))
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.collect::<Vec<String>>();
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Self {
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input: lines
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}
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}
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}
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impl Day18 {
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fn full_eval_lin(formula: String) -> i64 {
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return Self::eval_lin(&formula.chars().filter(|p| *p != ' ').collect(), 0).0;
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}
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fn eval_lin(formula: &Vec<char>, start_idx: usize) -> (i64, usize) {
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let mut curr: i64 = 0;
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let mut i = start_idx;
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loop {
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if i >= formula.len() || formula[i] == ')' {
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return (curr, i+1);
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}
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let mut op = '+';
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if i > start_idx {
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op = formula[i];
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i += 1;
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}
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let param: i64;
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if formula[i] == '(' {
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(param, i) = Self::eval_lin(formula, i+1);
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} else {
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param = formula[i].to_string().parse::<i64>().unwrap();
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i += 1;
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}
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match op {
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'+' => { curr += param; }
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'*' => { curr *= param; }
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_ => panic!()
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}
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}
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}
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}
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impl Day18 {
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// Shunting-yard Algorithm
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fn eval_advanced(formula: String) -> i64 {
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let mut operands: Vec<i64> = Vec::new();
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let mut operators: Vec<char> = Vec::new();
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for chr in formula.chars().filter(|p| *p != ' ') {
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if chr == '*' || chr == '+' {
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while !operators.is_empty() && chr <= *operators.last().unwrap() {
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let a = operands.pop().unwrap();
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let b = operands.pop().unwrap();
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let op = operators.pop().unwrap();
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operands.push(match op {
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'+' => a+b,
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'*' => a*b,
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_ => panic!(),
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});
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}
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operators.push(chr);
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} else if chr == '(' {
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operators.push(chr);
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} else if chr >= '0' && chr <= '9' {
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operands.push(chr.to_string().parse().unwrap());
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} else if chr == ')' {
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while *operators.last().unwrap() != '(' {
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let a = operands.pop().unwrap();
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let b = operands.pop().unwrap();
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let op = operators.pop().unwrap();
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operands.push(match op {
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'+' => a+b,
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'*' => a*b,
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_ => panic!(),
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});
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}
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operators.pop();
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} else {
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panic!();
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}
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}
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while !operators.is_empty() {
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let a = operands.pop().unwrap();
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let b = operands.pop().unwrap();
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let op = operators.pop().unwrap();
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operands.push(match op {
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'+' => a+b,
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'*' => a*b,
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_ => panic!(),
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});
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}
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return operands.pop().unwrap();
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}
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}
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impl AdventOfCodeDay for Day18 {
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fn task_1(&self) -> String {
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if is_verbose!() {
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for line in &self.input {
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verboseln!("{} := {:?}", line, Day18::full_eval_lin(line.to_owned()));
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}
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}
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return self.input.iter().map(|p| Day18::full_eval_lin(p.to_owned())).sum::<i64>().to_string();
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}
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fn task_2(&self) -> String {
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if is_verbose!() {
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for line in &self.input {
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verboseln!("{} := {:?}", line, Day18::eval_advanced(line.to_owned()));
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}
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}
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return self.input.iter().map(|p| Day18::eval_advanced(p.to_owned())).sum::<i64>().to_string();
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}
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} |