Faulty keyboard

String Simulation

80.0% acceptance

Feb 25, 2026

506

Your laptop keyboard is faulty, and whenever you type a character 'i' on it, it reverses the string that you have written. Typing other characters works as expected. You are given a 0-indexed string s, and you type each character of s using your faulty keyboard. Return the final string that will be present on your laptop screen.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn final_string(s: String) -> String {
    use std::collections::VecDeque;
    let mut dq: VecDeque<char> = VecDeque::new();
    let mut reversed = false;
    for c in s.chars() {
      if c == 'i' {
        reversed = !reversed;
      } else if reversed {
        dq.push_front(c);
      } else {
        dq.push_back(c);
      }
    }
    if reversed { dq.iter().rev().collect() } else { dq.iter().collect() }
  }
}