4个RE，捞一下！

#include <iostream>
using namespace std;

char s1[100], s2[100]; 

int main()
{
    int t = 0;
    cin >> s1;
    int i = 0;
    while (s1[i] != '\0')
    {
        if(s1[i] == '(')
        {
            cout << s1[i];
            s2[t] = s1[i];
            t++;        
        }
        if(s1[i] == ')')
        {
            if(t != 0)
            {
                cout << s1[i];
                t--;
            }
            else
            {
                cout << "(" << s1[i];           
            }       
        }
        i++;    
    }
    while(t != 0)
    {
        cout << ")";
        t--; 
    }   
    return 0;
}