题解 | #点击消除#

思路：

1.用栈，但是最总还需要倒序输出

2.用可变长的数组来模拟栈（StringBuilder）

代码：

public static void main(String[]args){
    Scanner in = new Scanner(System.in);
    char[] s= in.next().toCharArray();
    StringBuilder stack = new StringBuilder();
    for(int i = 0;i<s.length;i++){
        char c = s[i];
        if(stack.length()!=0 && stack.charAt(stack.length()-1)==c){
            //出栈
            stack.deleteCharAt(stack.length()-1);
        }else{
            //进栈
            stack.append(c);
        }
    }
    System.out.println(stack.length()==0?0:stack.toString());
}