package LeetCode;

import java.util.*;

public class LC_1047 {
    public static void main(String[] args) {
        System.out.println(new LC_1047().removeDuplicates("abbaca"));
    }

    public String removeDuplicates(String s) {
        Stack<Character> st = new Stack<>();
        if(s.length()==0) return "";
        for (int i = 0; i < s.length(); i++) {
            if (!st.isEmpty() && st.peek() == s.charAt(i)) st.pop();
            else if(st.isEmpty()) st.push(s.charAt(i));
            else st.push(s.charAt(i));
        }
        Object[] str = st.toArray();
        StringBuilder sb = new StringBuilder();
        for (Object o : str) {
            sb.append(o);
        }
        return sb.toString() ;
    }
}