You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
20 lines
720 B
20 lines
720 B
use std::collections::HashSet;
|
|
use std::io::{self, BufRead};
|
|
|
|
// Could be solved in O(n)
|
|
// (sort two copies of the list and walk it from the opposite ends to find a match)
|
|
// But O(n*log(n)) solution is much simpler.
|
|
fn main() {
|
|
let stdin = io::stdin();
|
|
let source_numbers: Vec<_> = stdin.lock().lines().into_iter()
|
|
.map(|line| line.unwrap().parse::<u32>().unwrap())
|
|
.collect();
|
|
|
|
let first_set: HashSet<_> = source_numbers.iter().map(|&number| number).collect();
|
|
let second_set: HashSet<_> = source_numbers.iter().map(|&number| 2020-number).collect();
|
|
|
|
let result = first_set.intersection(&second_set);
|
|
for value in result {
|
|
println!("{}", value * (2020-value));
|
|
}
|
|
}
|
|
|