Decode String LeetCode solution in Rust

1
impl Solution {
2
  pub fn decode_string(s: String) -> String {
3
    let mut stack: Vec<(usize, String)> = Vec::new();
4
    let (mut n, mut str) = (0, String::new());
5
    for c in s.chars() {
6
      match c {
7
        '[' => {
8
          stack.push((n, str.clone()));
9
          n = 0;
10
          str.clear();
11
        }
12
        ']' => {
13
          if let Some(last) = stack.pop() {
14
            str = last.1 + str.repeat(last.0).as_str();
15
          }
16
        }
17
        '0'..='9' => n = n * 10 + (c as u8 - b'0') as usize,
18
        c => str.push(c),
19
      }
20
    }
21
    str
22
  }
23
}