43 lines
1.2 KiB
Rust
43 lines
1.2 KiB
Rust
use std::fs::File;
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use std::io::{self, BufRead};
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use std::path::Path;
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use std::collections::HashMap;
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use std::env;
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fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
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where P: AsRef<Path>, {
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let file = File::open(filename)?;
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Ok(io::BufReader::new(file).lines())
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}
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fn main() {
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let mut occurrences: HashMap<i32, i32> = HashMap::new();
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let mut left_list: Vec<i32> = vec![];
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let mut right_list: Vec<i32> = vec![];
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let args: Vec<_> = env::args().collect();
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if let Ok(lines) = read_lines(args[1].clone()) {
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for line in lines.flatten() {
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let parts = line.split(" ").collect::<Vec<_>>();
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let lnum = parts[0].parse::<i32>().unwrap();
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let rnum = parts[1].parse::<i32>().unwrap();
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left_list.push(lnum);
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right_list.push(rnum);
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}
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for left_n in left_list {
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let entry = occurrences.entry(left_n).or_insert(0);
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for right_n in &right_list {
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if left_n == *right_n {
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*entry += 1;
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}
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}
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}
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let mut sum = 0;
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for (num, count) in &occurrences {
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sum += num * count;
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}
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println!("{}", sum)
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}
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}
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