I try the test all given of your suggestion,
such as (*),(+),(((()()()()()((((((()))))(*).....
my programme's answer is right!
but I still got WA!
Why?
who can help me to find my false!

the programm is below:
PS:If the symbol is '\n',I ignore it.Can I?

#include <stdio.h>
#include <iostream.h>
int gettype(char ch)
{
    if(ch=='+'||ch=='-'||ch=='/'||ch=='='||(ch>='0'&&ch<='9'))
return 1;
    else if(ch=='*') return 8;
    else if(ch=='(') return 9;
    else if(ch==')') return 0;
    else return 2;
}
void main()
{
    char *buf=new char[10000];
    int i=0,L,t,flag=0,tmp1,k=0;
    char ch,chtmp;
    ch=getchar();
    if(ch!='\n')
       buf[i++]=ch;
    while(ch!=EOF)
    {
        ch=getchar();
        if(ch!='\n')
            buf[i++]=ch;
    }
    buf[i-1]='\0';
    L=i-1;i=0;
    while(i<L-1)
    {
       ch=buf[i];
       if(ch=='(')
       {
           tmp1=i+1;chtmp=buf[tmp1];
           while(chtmp=='(') {tmp1++;chtmp=buf[tmp1];}
           if(gettype(chtmp)==1&&chtmp!='*')
           {
               chtmp=buf[i];t=gettype(chtmp);
               while(t!=2)
               {
                   if(t==9&&buf[i+1]=='*')
                   {
                       i+=2;
                       while(buf[i]!
='*'&&buf[i+1]!=')'&&i<L)
                           i++;
                       if(buf[i]!='*'&&buf
[i+1]!=')') {flag=1;cout<<"NO";return;}
                       i+=2;
                   }
                   else if(t==9&&buf[i+1]!='*')
{k++;i++;}
                   else if(t==0) {k--;i++;}
                   else if(t==2)
{flag=1;cout<<"NO";return;}
                   else i++;
                   chtmp=buf[i];t=gettype(chtmp);

               }
               if(k!=0) {cout<<"NO";return;}
           }
           else if(chtmp=='*')
           {
             i+=2;
             while(buf[i]!='*'&&buf[i+1]!=')'&&i<L) i++;
             if(buf[i]!='*'||buf[i+1]!=')')
{cout<<"NO";return;}
             i+=2;
           }
           else i++;
       }
       else i++;
    }
    cout<<"YES\n";
}

You return YES on this test

))((

Good luck.