输入为：

字符串

例子：(1+2)/(0.5+1)

输出：true | false

例子：true

(1+2)/(0.5+1)

True

  Java方法1：

import java.util.Scanner;

import java.util.Stack;

 

public class Main

{

  public static void main(String[] args)

  {

    Scanner sc = new Scanner(System.in);

    while (sc.hasNext())

    {

     

      /** 利用栈先进后出(FILO)特性*/

      Stack<Character> stack = new Stack<>();

      String str = sc.nextLine();

      char[] cs = str.toCharArray();

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

      {

         if (cs[i] == '(' || cs[i] == '{' || cs[i] == '[')

         {

           stack.push(cs[i]);

         }

         else

         {

           if (cs[i] == ')')

           {

             if (stack.peek() == '(')

             {

               stack.pop();

             }

           }

 

           if (cs[i] == '}')

           {

             if (stack.peek() == '{')

             {

               stack.pop();

             }

           }

           if (cs[i] == ']')

           {

             if (stack.peek() == '[')

             {

               stack.pop();

             }

           }

         }

      }

      if(stack.isEmpty()){

         System.out.println("true");

      }

      else{

         System.out.println("false");

      }

     

    }

  }

 

Java方法2

import java.util.Scanner;

 

public class  Main {

  public static void main(String[] args){

        Scanner sc=new Scanner(System.in);

        while(sc.hasNext())

        {

        String str=sc.nextLine();

            countBrackets(str);

        }

       

    }

 

  /** 判断该字符串括号是否成对出现，且嵌套关系正确*/

    public static void countBrackets(String str){

        int Big=0,Mid=0,Min=0;

       

        char[] charArr = str.toCharArray();

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

            if(charArr[i]=='{'){

              Big+=1;

            }

            if(charArr[i]=='['){

              Mid+=1;

            }

            if(charArr[i]=='('){

              Min+=1;

            }

            if(charArr[i]=='}'){

              Big-=1;

            }

            if(charArr[i]==']'){

              Mid-=1;

            }

            if(charArr[i]==')'){

              Min-=1;

            }

            if(Big<0||Mid<0||Min<0){

              System.out.println("false");

                return ;

            }

        }

        if(Big!=0||Mid!=0||Min!=0){

            System.out.println("false");

        }else{

            System.out.println("true");

        }

    }

C++方法1

#include <iostream>

#include <string>

#include <stack>

using namespace std;

int main()

{

    stack <char> sta;

    string s;

    cin>>s;

    for(int i=0;i<s.length();i++)

    {

        if(s[i]=='('||s[i]=='{'||s[i]=='[')

            sta.push(s[i]);

        else

        {

            if(s[i]==')')

            {

                if(sta.top()=='(')

                    sta.pop();

            }

            if(s[i]=='}')

            {

                if(sta.top()=='{')

                    sta.pop();

            }

            if(s[i]==']')

            {

                if(sta.top()=='[')

                    sta.pop();

            }

        }

    }

    if(sta.empty())

        cout<<"true"<<endl;

    else

        cout<<"false"<<endl;

    return 0;

}