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use std::io;
fn main() -> io::Result<()> {
let eqns = io::stdin()
.lines()
.flatten()
.collect::<Vec<_>>()
.iter()
.map(|line| line.split_once(": ").unwrap())
.map(|(ans, nums)| {
(
ans.parse::<u64>().unwrap(),
nums.split_whitespace()
.map(|s| s.parse::<u64>().unwrap())
.collect::<Vec<_>>(),
)
})
.collect::<Vec<_>>();
let silver: u64 = eqns.iter().map(crate::silver).sum();
let gold: u64 = eqns.iter().map(crate::gold).sum();
println!("silver: {silver}");
println!("gold: {gold}");
return Ok(());
}
fn concat(x: &u64, y: &u64) -> u64 {
x * (10u64.pow(y.ilog10() + 1)) + y
}
fn calibration(want: u64, x: &u64, y: &u64, rest: &[u64], gold: bool) -> bool {
if *x > want {
return false;
}
match rest {
[] => want == x + y || want == x * y || (gold && want == concat(x, y)),
[z, rest @ ..] => {
calibration(want, &(x + y), z, rest, gold)
|| calibration(want, &(x * y), z, rest, gold)
|| (gold && calibration(want, &concat(x, y), z, rest, gold))
}
}
}
fn silver((want, nums): &(u64, Vec<u64>)) -> u64 {
match nums.as_slice() {
[x, y, rest @ ..] => {
if calibration(*want, x, y, rest, false) {
*want
} else {
0
}
}
_ => 0,
}
}
fn gold((want, nums): &(u64, Vec<u64>)) -> u64 {
match nums.as_slice() {
[x, y, rest @ ..] => {
if calibration(*want, x, y, rest, true) {
*want
} else {
0
}
}
_ => 0,
}
}
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