struct Solution; impl Solution { pub fn remove_duplicates(s: String) -> String { let mut ans = String::new(); for c in s.chars() { if ans.len() > 0 && ans.chars().last() == Some(c) { ans.pop(); } else { ans.push(c); } } ans } } fn main() { let s = "abbaca".to_string(); print!("{}", Solution::remove_duplicates(s)); }