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37 lines
853 B
37 lines
853 B
use std::collections::HashSet;
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use std::error;
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use std::fs::File;
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use std::io::BufRead;
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use std::io::BufReader;
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fn set_from_str(chars: &str) -> HashSet<u32> {
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HashSet::from_iter(chars.chars().map(|c| if c.is_uppercase() { c as u32 - 38 } else { c as u32 - 96 }))
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}
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fn main() -> Result<(), Box<dyn error::Error>> {
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let f = File::open("input.txt")?;
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let reader = BufReader::new(f);
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let mut sum: u32 = 0;
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let mut group_items: HashSet<u32> = HashSet::new();
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for (i, line) in reader.lines().enumerate() {
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let line = line?;
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if group_items.is_empty() {
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group_items = set_from_str(line.as_str());
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} else {
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group_items = set_from_str(line.as_str()).intersection(&group_items).cloned().collect();
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}
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if (i + 1) % 3 == 0 {
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sum += group_items.iter().next().unwrap();
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group_items.drain();
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}
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}
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println!("{}", sum);
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Ok(())
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}
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