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(); }
}