括号匹配 “亲兄弟”-＞点击消除

public static void main(String[] args) {
        /**
         方法一：
         */
        Scanner in = new Scanner(System.in);
        char[] s = in.next().toCharArray();

        Stack<Character> stack = new Stack<Character>();
        Stack<Character> stack2 = new Stack<Character>();//辅助stack栈数据输出顺序字符串

        for(int i = 0; i < s.length; i++) {

            if(!stack.isEmpty() && s[i] == stack.peek()){
                stack.pop();
            }else{
                stack.push(s[i]);
            }
        }

        if(stack.isEmpty()){
            System.out.print(0);
        }

        while(!stack.isEmpty()){
            stack2.push(stack.pop());
        }
        while(!stack2.isEmpty()){
            System.out.print(stack2.pop().toString());
        }


    }

/**
     方法二：用StringBuilder模拟栈：
     */
    public static void main2(String[] args){
        Scanner in = new Scanner(System.in);
        char[] s = in.next().toCharArray();

        //用StringBuilder模拟栈
        StringBuilder st = new StringBuilder();
        for(int i = 0; i < s.length; i++) {
            char ch = s[i];
            if(st.length() != 0 && ch == st.charAt(st.length()-1)){
                //模拟出栈
                st.deleteCharAt(st.length()-1);
            }else{
                //模拟入栈
                st.append(ch);
            }
        }

        System.out.println(st.length() == 0 ? 0 : st.toString());
    }