括号配对问题-java:Stack

package Combat.com;

import java.util.Enumeration;
import java.util.Scanner;
import java.util.Stack;

public class Main
{
    public static void main(String []args)
    {
        Scanner cin = new Scanner(System.in);
        int N = cin.nextInt();
        for(int i = 0; i < N; i++)
        {
            String str = cin.next();
            AchieceStack(str);
        }
    }
    static void AchieceStack(String str)
    {
        if(str.charAt(0) == ‘]‘ || str.charAt(0) == ‘)‘)//第一个就出现不匹配
        {
            System.out.println("No");
            return;
        }
        Stack stack = new Stack();
        int len = str.length();
        stack.push(str.charAt(0));
        for(int i = 1; i < len; i++)
        {
            if(str.charAt(i) == ‘[‘ || str.charAt(i) == ‘(‘)//左括号压栈
            {
                stack.push(str.charAt(i));
            }
            else//右括号判断
            {
                if(stack.empty() || stack.size() > len-i)//特殊判断条件。
                {
                    System.out.println("No");
                    return;
                }
                char c = (char) stack.peek();
                if(c == ‘[‘ && str.charAt(i) == ‘]‘)
                {
                    stack.pop();
                }
                else if(str.charAt(i) == ‘)‘ && c == ‘(‘)
                {
                    stack.pop();
                }
                else
                {
                    System.out.println("No");
                    return;
                }
            }
            /*Enumeration items=stack.elements();//这部分代码用来检验的，很重要
            //显示枚举(stack)中的所有元素
            while(items.hasMoreElements())
            {
                System.out.print(items.nextElement()+"");
            }
            System.out.println();*/
        }
        if(!stack.empty())
        {
            System.out.println("No");
        }
        else
        {
            System.out.println("Yes");
        }
    }
}