22 lines
617 B
Rust
22 lines
617 B
Rust
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use std::collections::HashMap;
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use std::io;
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fn main() -> io::Result<()> {
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let mut l1: Vec<u64> = vec!();
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let mut l2: HashMap<u64, u64> = HashMap::default();
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for line in io::stdin().lines() {
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let line = line?;
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let parts: Vec<&str> = line.trim().split_whitespace().collect();
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let (n1, n2) = (parts[0], parts[1]);
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l1.push(n1.parse().unwrap());
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let v = l2.entry(n2.parse::<u64>().unwrap()).or_insert(0);
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*v += 1;
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}
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let mut sum = 0;
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for n1 in l1.into_iter() {
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sum += n1*l2.get(&n1).unwrap_or(&0);
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}
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println!("{}", sum);
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Ok(())
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}
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