Reverse substrings between each pair of parentheses

String Stack

71.9% acceptance

Feb 25, 2026

2940

129

You are given a string s that consists of lower case English letters and brackets. Reverse the strings in each pair of matching parentheses, starting from the innermost one. Your result should not contain any brackets.

Solution

Rust

Time O(n * m)

Space O(n * m)

LeetCode

solution.rs

impl Solution {
  pub fn reverse_parentheses(s: String) -> String {
    let mut stack: Vec<Vec<u8>> = vec![vec![]];
    for c in s.bytes() {
      match c {
        b'(' => stack.push(vec![]),
        b')' => {
          let mut top = stack.pop().unwrap();
          top.reverse();
          stack.last_mut().unwrap().extend_from_slice(&top);
        }
        ch => stack.last_mut().unwrap().push(ch),
      }
    }
    String::from_utf8(stack.pop().unwrap()).unwrap()
  }
}