1047. Remove All Adjacent Duplicates In String

/*
1047. Remove All Adjacent Duplicates In String
Runtime: 22 ms, faster than 46.41% of Java online submissions for Remove All Adjacent Duplicates In String.
Memory Usage: 39.2 MB, less than 91.53% of Java online submissions for Remove All Adjacent Duplicates In String.
*/

class Solution {
    public String removeDuplicates(String S) {
        Stack<Character> stack=new Stack<>();
        
        for(char c:S.toCharArray())
        {
            if(!stack.empty() && stack.peek()==c )
                stack.pop();
            else   
            stack.push(c);
                        
        }
        StringBuilder s=new StringBuilder();
         
        
        while(!stack.empty())
        {
            s.append(stack.pop());
        }
        s=s.reverse();
        
        return s.toString();
        
    }
}