@[ZBXALQX](/user/1070547)
```
#include<bits/stdc++.h>
using namespace std;
int main (){
char a;
int sum=0,i=0;
while(1){
cin>>a;
if(a=='@')break;
i++;
if(a=='(')sum++;
if(a==')'){
sum--;
if(sum<0){//要判断sum<0
cout<<"NO"<<endl;
return 0;
}
}
}
if(sum==0)cout<<"YES"<<endl;
else cout<<"NO"<<endl;
return 0;
}
```
by mc_xiexie @ 2024-04-13 12:31:01
@[ZBXALQX](/user/1070547)
你觉得`())(`可以吗？
by mc_xiexie @ 2024-04-13 12:32:26
@[mc_xiexie](/user/1095322) 谢谢
by ZBXALQX @ 2024-04-13 12:35:35