2019携程校招笔试

package com.nps.base.xue.DataStructure.list;

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Main {


    /*请完成下面这个函数，实现题目要求的功能
    当然，你也可以不按照下面这个模板来作答，完全按照自己的想法来 ^-^
    ******************************开始写代码******************************/
    static String resolve(String expr) {
        Stack<String> stack1 = new Stack<>();
        Queue<String> queue = new ArrayDeque<>() ;
        String token;
        int zuo = 0;
        Scanner parser = new Scanner(expr);
        for (int i = 0; i < expr.length(); i++) {
            token = String.valueOf(expr.charAt(i));
            if (token.equals("(")){
                zuo++;
                stack1.push(token);
            }else if (!token.equals(")") && !token.equals("(")){
                stack1.push(token);
            }else {
                while (!stack1.peek().equals("(") && zuo != 1){
                    queue.add(stack1.pop());
                    if (stack1.peek().equals("(")){
                        stack1.pop();
                        zuo--;
                        if (zuo == 1)
                            stack1.pop();
                        break;
                    }
                }
                while (!queue.isEmpty()){
                    stack1.push(queue.poll());
                }
            }
        }
        expr = "";
        while (!stack1.empty()){
            expr += stack1.pop();
        }
        return expr;
    }
    /******************************结束写代码******************************/


    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        String res;

        String _expr;
        try {
            _expr = in.nextLine();
        } catch (Exception e) {
            _expr = null;
        }

        res = resolve(_expr);
        System.out.println(res);
    }
}