31 lines
693 B
Rust
31 lines
693 B
Rust
use std::io::{read_to_string, stdin};
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fn main() {
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let temp = read_to_string(stdin()).unwrap();
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let mut iter = temp
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.split_ascii_whitespace()
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.map(|x| x.parse::<usize>().unwrap());
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let n = iter.next().unwrap();
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let mut ta = iter.next().unwrap();
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let mut tv = 0;
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let mut items = (0..n)
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.map(|_| (iter.next().unwrap(), iter.next().unwrap()))
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.collect::<Vec<_>>();
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items.sort();
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while ta > 0 && items.len() > 0 {
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let (v, a) = items.pop().unwrap();
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if a >= ta {
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tv += v * ta;
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ta = 0;
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} else {
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tv += v * a;
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ta -= a;
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}
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}
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println!("{}", tv);
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}
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