Kees van Kempen
ce39b976ab
This is my very first piece of Rust code. When it compiled for the first time, the result was what it should be, so I am happy :-). It did take me > 1 hour to solve this...
42 lines
906 B
Rust
42 lines
906 B
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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fn main() {
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let mut sum = 0;
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let mut mus = 0;
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if let Ok(lines) = read_lines("./input") {
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for line in lines {
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if let Ok(text) = line {
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sum = sum + first_digit(&text);
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mus = mus + last_digit(&text);
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}
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}
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}
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println!("{}", 10*sum + mus);
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}
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// TODO: Switch to Option(i32) to allow not having a digit in text <https://doc.rust-lang.org/std/option/>.
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fn first_digit(text: &String) -> i32 {
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for c in text.chars() {
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if c.is_digit(10) {
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return c.to_digit(10).unwrap() as i32;
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}
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}
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// TODO: What if there is no digit?
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0
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}
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fn last_digit(text: &String) -> i32 {
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let txet = &mut text.chars().rev().collect();
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first_digit(txet)
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}
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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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