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Day 18 part 1 (fixed)

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This commit is contained in:
Bill Thiede 2020-12-26 15:19:23 -08:00
parent 4e9e90c096
commit 992fcb01be
1 changed files with 11 additions and 21 deletions
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32
2020/src/day18.rs
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@ -112,15 +112,23 @@ mod part1 {
}; };
} }
fn parse_term(tokens: &mut VecDeque<Token>) -> u64 { pub fn parse_expression(tokens: &mut VecDeque<Token>) -> u64 {
let mut result = parse_item(tokens); let mut result = parse_item(tokens);
let mut t = tokens[0]; let mut t = tokens[0];
loop { loop {
match t { match t {
Token::Mul | Token::Add => { Token::Mul => {
tokens.pop_front(); tokens.pop_front();
let rhs = parse_item(tokens); let rhs = parse_item(tokens);
if let Token::Mul = t { if let Token::Mul = t {
result = result * rhs;
}
t = tokens[0];
}
Token::Add => {
tokens.pop_front();
let rhs = parse_item(tokens);
if let Token::Add = t {
result = result + rhs; result = result + rhs;
} }
t = tokens[0]; t = tokens[0];
@ -130,26 +138,8 @@ mod part1 {
} }
result result
} }
pub fn parse_expression(tokens: &mut VecDeque<Token>) -> u64 {
let mut result = parse_term(tokens);
let mut t = tokens[0];
loop {
match t {
Token::Mul | Token::Add => {
tokens.pop_front();
let rhs = parse_term(tokens);
if let Token::Add = t {
result = result * rhs;
}
t = tokens[0];
}
_ => break,
}
}
result
}
} }
fn parse_part1(tokens: &[Token]) -> u64 { fn parse_part1(tokens: &[Token]) -> u64 {
let mut vd: VecDeque<Token> = tokens.into_iter().cloned().collect(); let mut vd: VecDeque<Token> = tokens.into_iter().cloned().collect();
part1::parse_expression(&mut vd) part1::parse_expression(&mut vd)