题目

方法一：利用栈做匹配

class Solution {
    public String removeDuplicates(String s) {
        Deque<Character> deque = new LinkedList<>();
        StringBuffer str = new StringBuffer();
        for(int i = 0 ; i < s.length() ;  i++){
            if(!deque.isEmpty() && deque.peek() ==s.charAt(i)) deque.pop();
            else deque.push(s.charAt(i));
        }
        while(!deque.isEmpty()){
            str.append(deque.pop());
        }
        return str.reverse().toString();
    }
}

方法二：消消乐

class Solution {
    public String removeDuplicates(String s) {
      
        StringBuffer str = new StringBuffer(s);
        for(int i = 0 ; i <str.length() ; i++){
            if(i>0 && str.charAt(i) == str.charAt(i-1)) {
                str.delete(i-1,i+1);//删除重复元素
                i = i-2;//向前回退两个位置
            }
        }
        return str.toString(); 
    }
}