Clear digits

String Stack Simulation

82.7% acceptance

Feb 24, 2026

691

You are given a string s. Your task is to remove all digits by doing this operation repeatedly: Delete the first digit and the closest non-digit character to its left. Return the resulting string after removing all digits. Note that the operation cannot be performed on a digit that does not have any non-digit character to its left.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn clear_digits(s: String) -> String {
    let mut stack: Vec<char> = Vec::new();
    for c in s.chars() {
      if c.is_ascii_digit() {
        stack.pop(); // remove closest non-digit character to the left
      } else {
        stack.push(c);
      }
    }
    stack.into_iter().collect()
  }
}