题解(栈解法)

#include<bits/stdc++.h>
using namespace std;
char s[265];
int TOP=0;
int main(){
	char x;
	while(cin>>x){
		if(x=='@') break;
		if(TOP==0){
			if(x==')'){
				cout<<"NO";
				return 0;
			}
		}if(x=='(')s[++TOP]=x;
		if(x==')')--TOP;
	}if(TOP==0) cout<<"YES";
	else cout<<"NO";
	return 0;
}