LeetCode 1209. Remove All Adjacent Duplicates in String II

Problem Statement

impl Solution {
    pub fn remove_duplicates(s: String, k: i32) -> String {
        let mut stack = vec![(0, '#')];
        let mut ans = "".to_string();
        for c in s.chars() {
            let index = stack.len() - 1;
            if stack[index].1 != c {
                stack.push((1, c));
            } else if stack[index].0 == k - 1 {
                stack.pop();
            } else {
                let mut val = stack[index];
                val.0 += 1;
                stack[index] = val;
            }
        }

        for item in stack {
            ans.push_str(&(0..item.0 as usize).map(|_| item.1).collect::<String>());
        }
        return ans;
    }
}