棧的應用

 

#include<iostream>
#include<cstdio>
using namespace std;
//ifstream cin ("c.in");
//ofstream cout ("c.out");
const int MAXSIZE=200;
class Sqstack
{
    private:
        char elem[MAXSIZE];
        int top;
    public:
        Sqstack(){top=0;}
        ~Sqstack(){};
        void SetEmpty(){top=0;}//制棧爲空
        int IsEmpty();
        void push(char e);
        char pop();
        char Getpop();
};
int  Sqstack::IsEmpty()
{
    if(top==0)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}
void Sqstack::push(char e)
{
    top++;
    elem[top]=e;
}
char Sqstack::pop()
{
    char x=elem[top];
    top--;
    return x;
}
char Sqstack::Getpop()
{
    return elem[top];
}




int main()
{
    int t;
    string a;

    cin>>t;
    int correct = 1;
    getchar();//吸收回車

    while(t--)
    {
        Sqstack stk;
        correct=1;

        getline(cin,a);
        for(int i=0;i<a.length();i++)
        {
            if(a[i]=='('||a[i]=='[')
            {
                stk.push(a[i]);
            }
            else if(a[i]==')')
            {
                if(stk.Getpop()!='('||stk.IsEmpty())
                   {
                       correct=0;
                       break;
                   }
                   stk.pop();
            }
            else if(a[i]==']')
            {
                if(stk.Getpop()!='['||stk.IsEmpty())
                {
                    correct=0;
                    break;
                }
                stk.pop();
            }
        }
        if(!stk.IsEmpty())
        {
            correct=0;
        }
        if(correct)
        {
            cout<<"Yes"<<endl;
        }
        else
        {
            cout<<"No"<<endl;
        }
    }
}