Monistus

use std::io::BufRead;

fn main() -> std::io::Result<()> {
    let mut input = std::io::BufReader::new(std::io::stdin());
    let mut phrase: String = "".to_string();
    input.read_line(&mut phrase)?;

    println!("{}", process_string_rec(&phrase));

    Ok(())
}

fn process_string_rec(input: &str) -> String {
    if input.chars().all(|x| !x.is_ascii_digit()) {
        return input.to_owned();
    }
    let num_index_char = input
        .char_indices()
        .find(|(_index, character)| character.is_ascii_digit())
        .unwrap();
    let (before_num, after_num) = input.split_at(num_index_char.0);

    let num_as_char: usize = num_index_char.1.to_digit(10).unwrap() as usize;
    let copied_segment: String = after_num
        .chars()
        .skip(1)
        .take(num_as_char)
        .collect::<String>();
    process_string_rec(
        &[
            before_num,
            &copied_segment,
            &after_num.chars().skip(1).collect::<String>(),
        ]
        .concat(),
    )
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 1, 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: RUNTIME ERROR

Test 10

Group: 2

Verdict: RUNTIME ERROR

Test 11

Group: 2

Verdict: RUNTIME ERROR

Test 12

Group: 2

Verdict: RUNTIME ERROR

Test 13

Group: 2

Verdict: RUNTIME ERROR

Test 14

Group: 2

Verdict: RUNTIME ERROR