代码

#include<bits/stdc++.h>
using namespace std ;

int T , n ;
unsigned long long x ;

string s ;

stack < unsigned long long > ss ;

int main()
{
	ios::sync_with_stdio( false ) ;
	cin.tie( 0 ) ;
	cout.tie( 0 ) ;
	cin >> T ;
	for( int i = 1 ; i <= T ; i++ )
		{
			cin >> n ;
			for( int i = 1 ; i <= n ; i++ )
				{
					cin >> s ;
					if( s == "push" )
						{
							cin >> x ;
							ss.push( x ) ;
						}
					else if( s == "pop" )
						{
							if( ss.empty() )	
								cout << "Empty" << "\n" ;
							else	
								ss.pop() ;
						}
					else if( s == "query" )
						{
							if( ss.empty() )
								cout << "Anguei！" << "\n" ;
							else	
								cout << ss.top() << "\n" ;
						}
					else
						cout << ss.size() << "\n" ;
				}
		}
}