1175B - Catch Overflow - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int long long
#define inf 0x3f3f3f3f
#define fi first
#define se second
#define eps 1e-6
const int N=2e5+5;
const int maxx=1ll<<32;
void solve()
{
	int n;
	cin>>n; 
	getchar(); 
	vector<int>st={1};
	int sum=1;
	int x=0;
	int tp=0;
	for(int i=1;i<=n;i++)
	{
		string s;
		cin>>s;
		if(s=="add")
		{
			x+=sum*st.back();
		}
		else if(s=="for")
		{
			int k;
			cin>>k;
			st.push_back(min(maxx,k*st.back()));
			//这里刚好是，再哪一层能够乘以相应层数	
		}
		else st.pop_back();
	}
	if(x>=maxx) cout<<"OVERFLOW!!!"<<endl;
	else cout<<x<<endl;
}
signed main()
{
	int T;
	T=1;
//	cin>>T;	
	while(T--)
	{
		solve();
	} 
	return 0;
}