使用堆栈检查括号/括号

Posted 2023-02-21

【中文标题】使用堆栈检查括号/括号

【英文标题】：Parenthesis/Bracket checking using stack

【发布时间】：2022-01-02 05:53:49

【问题描述】：

我正在使用字符串检查字符串中的平衡括号。我已经使用类制作了实现堆栈。首先，当我使用 util 包运行该程序时，它给出了正确的答案，但是当我制作自定义堆栈时，这给出了错误的输出。我在这方面做错了什么..

import java.util.Scanner;

public class Stack 
    int top;
    char []a=new char[10];
    
    public void push(char c)
     
        if(top <a.length-1)
         
            top++;
             a[top]=c;
         
     
    
    public char pop()
     
         if(top > 0)
         
             top--;
             char c=a[top];
             return c;
         
        return 0;
         
     
    
    public boolean isEmpty()
     
        return (top==-1);
     
    
    public char peek()
     
        return a[top];
     
    
    void displayStack()
    
        for(int i=0;i<=top;i++)
          System.out.print(a[i]+" ");
    
    public static boolean CheckParentesis(String str)
    
        if (str.isEmpty())
            return true;

        Stack stack = new Stack();
        for (int i = 0; i < str.length(); i++)
        
            char Symbol = str.charAt(i);
            if (Symbol == '' || Symbol == '(' || Symbol == '[')
            
                stack.push(Symbol);
                continue;
            
            
            if (Symbol == '' || Symbol == ')' || Symbol == ']')
            
                if (stack.isEmpty())
                    return false;

                char last = stack.peek();     //peek checks top element of stack without removing it...
                if (Symbol == '' && last == '' || Symbol == ')' && last == '(' || Symbol == ']' && last == '[')
                    stack.pop();
                     
                else 
                    return false;
            
        
        
        return stack.isEmpty();
    
    
    public static void main(String[] args) 
          
            Scanner sc = new Scanner(System.in);          
            String[] str = new String [sc.nextInt()];      
            //consuming the <enter> from input above  
            sc.nextLine();   

            for (int i = 0; i < str.length; i++)   
              
              str[i] = sc.nextLine();  
             
            for(String s: str)   
              
                if(CheckParentesis(s)==true)
                       System.out.println("TRUE"); 
                   else
                      System.out.println("FALSE");
              
          
        
    

示例输入：

4

(the[is]valid)

(the[is]valid))

the(is[valid])

(this](isvalid)

样本输出：

是的

错误

是的

错误

【问题讨论】：

“为什么我的代码不起作用？”这不是我们想要的问题。你可以说得更详细点吗？你试过调试吗？

【参考方案1】：

错误

您没有使用静态函数或全局变量 您必须在每次新字符串检查后将 top 重置为 -1 在执行 pop() 时，您应该首先捕获元素，然后减少堆栈索引值

import java.util.Scanner;

public class Stack 
    static int top = -1;
    static char[] a = new char[10];

    public static void clear() 
        top = -1;
    

    public static void push(char c) 
        if (top < a.length - 1) 
            top++;
            a[top] = c;
        
    

    public static char pop() 
        if (top >= 0) 

            char c = a[top];
            top--;
            return c;
        
        return 0;

    

    public static boolean isEmpty() 
        return (top == -1);
    

    public static char peek() 
        return a[top];
    

    static void displayStack() 
        for (int i = 0; i <= top; i++)
            System.out.print(a[i] + " ");
        System.out.println();
    

    public static boolean CheckParentesis(String str) 
        if (str.isEmpty())
            return true;

        Stack stack = new Stack();
        stack.clear();
        for (int i = 0; i < str.length(); i++) 
            // stack.displayStack();
            char Symbol = str.charAt(i);
            if (Symbol == '' || Symbol == '(' || Symbol == '[') 
                stack.push(Symbol);
                continue;
            

            if (Symbol == '' || Symbol == ')' || Symbol == ']') 
                if (stack.isEmpty())
                    return false;

                char last = stack.peek(); //peek checks top element of stack without removing it...
                if (
                    (Symbol == '' && last == '') ||
                    (Symbol == ')' && last == '(') ||
                    (Symbol == ']' && last == '[')
                )
                    stack.pop();

                else
                    return false;
            

        
        return stack.isEmpty();
    

    public static void main(String[] args) 
        
            Scanner sc = new Scanner(System.in);
            String[] str = new String[sc.nextInt()];
            //consuming the <enter> from input above  
            sc.nextLine();

            for (int i = 0; i < str.length; i++) 
                str[i] = sc.nextLine();
            
            for (String s: str) 
                if (CheckParentesis(s) == true)
                    System.out.println("TRUE");
                else
                    System.out.println("FALSE");