AC的不是我的

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 1001
int main()
{
    char s[N], a[N];
    while(gets(s))
    {
        int len,i,top = 0;
        len= strlen(s);
        for(i = 0; i < len; i++)
        {
            //
            if(s[i] == '(' || s[i] == '[' || s[i] == '{')
            {
                a[++top] = s[i];
            }
            else if(s[i] == ')')
            {
                if(a[top] == '(')
                    top--;
                else
                {
                    top++;
                    break;
                }
            }
            else if(s[i] == ']')
            {
                if(a[top] == '[')
                    top--;
                else
                {
                    top++;
                    break;
                }
            }
            else if(s[i] == '}')
            {
                if(a[top] == '{')
                    top--;
                else
                {
                    top++;
                    break;
                }
            }
        }
        if(top!=0)
         printf("no\n");
        else
        printf("yes\n");
    }
    return 0;
}

 

我的没过：

#include <bits/stdc++.h>
using namespace std;
int main()
{

    char a[55];
    while (scanf("%s", a) != EOF)
    {

        stack<char> b;
        int len = strlen(a);
        int flag = 0;
        for (int i = 0; i < len; i++)
        {
            if (a[i] == '(' || a[i] == '[' || a[i] == '{')
                b.push(a[i]);
            // if (!b.empty())
            // {
            //     if (b.top() == '(' && a[i] == ')')
            //         b.pop();
            //     else if (b.top() == '{' && a[i] == '}')
            //         b.pop();
            //     else if (b.top() == '[' && a[i] == ']')
            //         b.pop();
            // }
            if (!b.empty())
            {
                if (a[i] == ')')
                    if (b.top() == '(')
                        b.pop();

                    else
                    {
                        flag = 1;
                        break;
                    }
                else if (a[i] == ']')
                    if (b.top() == '[')
                        b.pop();

                    else
                    {
                        flag = 1;
                        break;
                    }
                else if (a[i] == '}')
                    if (b.top() == '{')
                        b.pop();

                    else
                    {
                        flag = 1;
                        break;
                    }
            }
        }

        if (flag)
        {

            printf("no\n");
        }
        else
        {

            if (b.empty())
            {
                printf("yes\n");
            }
            else
                printf("no\n");
        }
    }

    return 0;
}