3
pair pair int int int

pair<pair<int,int>,int>

 1 #include<iostream> 2 #include<cstring> 3 #include<sstream> 4 #include<vector> 5 using namespace std; 6 #define FOR(i,j,k) for(int i=j;i<=k;i++) 7 #define FORD(i,j,k) for(int i=j;i>=k;i--) 8 #define maxn 100010 9 #define SZ(x) int(x.size())10 int k;11 int a[maxn];12 pair<int,int> res[maxn];13 vector<int> zz;14 string s;15 stringstream ss,ans;16 void cq(int l)17 {18     if(a[l])19     {20         ans<<"pair<";21         cq(res[l].first);22         ans<<‘,‘;23         cq(res[l].second);24         ans<<‘>‘;25     }26     else ans<<"int";27     return;28 }29 int main()30 {31     getline(cin,s);32     getline(cin,s);33     ss<<s;34     while(!ss.eof())35     {36         ss>>s;37         a[++k]=(s=="pair");38     }39     FORD(i,k,1)40     {41         if(a[i])42         {43             if(SZ(zz)<2)44             {45                 cout<<"Error occurred"<<endl;46                 return 0;47             }48             res[i].first=zz.back();49             zz.pop_back();50             res[i].second=zz.back();51             zz.pop_back();52         }53         zz.push_back(i);54     }55     if(SZ(zz)>1) {    56             cout<<"Error occurred"<<endl;57             return 0;58             }59     cq(1);60     cout<<ans.str();61     return 0;62 }

 1 #include<iostream> 2 #include<cstring> 3 #include<sstream> 4 using namespace std; 5 #define FOR(i,j,k) for(int i=j;i<=k;i++) 6 #define FORD(i,j,k) for(int i=j;i>=k;i--) 7 #define maxn 100010 8 #define SZ(x) int(x.size()) 9 string s;10 stringstream ss,ans;11 bool cq()12 {13     if(ss.eof()) return false;14     ss>>s;15     if(s=="pair")16     {17         ans<<"pair<";18         if(!cq()) return false;19         ans<<‘,‘;20         if(!cq()) return false;21         ans<<‘>‘;22     }23     else ans<<"int";24     return true;25 }26 27 int main()28 {29     getline(cin,s);30     getline(cin,s);31     ss<<s;32     if(cq()&&ss.eof()) cout<<ans.str(); else cout<<"Error occurred"<<endl;33     return 0;34 }