/in/foo.cc:30:5: error: invalid use of template-name 'std::vector' without an argument list
     vector son;
     ^~~~~~
/in/foo.cc:30:5: note: class template argument deduction is only available with -std=c++1z or -std=gnu++1z
In file included from /usr/include/c++/7/vector:64:0,
                 from /usr/include/c++/7/queue:61,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:86,
                 from /in/foo.cc:1:
/usr/include/c++/7/bits/stl_vector.h:216:11: note: 'template<class _Tp, class _Alloc> class std::vector' declared here
     class vector : protected _Vector_base<_Tp, _Alloc>
           ^~~~~~
/in/foo.cc: In function 'node* insertT(node*, trg&)':
/in/foo.cc:106:27: error: 'struct node' has no member named 'son'
     for(int i = 0; i < h->son.size(); i++)
                           ^~~
/in/foo.cc:108:16: error: 'struct node' has no member named 'son'
         t = h->son[i];
                ^~~
/in/foo.cc:111:16: error: 'struct node' has no member named 'son'
             h->son[i] = insertT(t, a);
                ^~~
/in/foo.cc:112:16: error: 'struct node' has no member named 'son'
             h->son[i]->h = h->h + 1;
                ^~~
/in/foo.cc:116:16: error: 'struct node' has no member named 'son'
     int p = h->son.size();
                ^~~
/in/foo.cc:117:8: error: 'struct node' has no member named 'son'
     h->son.PB(insertT(NULL, a));
        ^~~
/in/foo.cc:118:8: error: 'struct node' has no member named 'son'
     h->son[p]->h = h->h + 1;
        ^~~
/in/foo.cc: In function 'double dfs(node*, int)':
/in/foo.cc:130:32: error: 'struct node' has no member named 'son'
         for (int i = 0; i < h->son.size(); i++)
                                ^~~
/in/foo.cc:131:27: error: 'struct node' has no member named 'son'
             sum += dfs(h->son[i], k);
                           ^~~
/in/foo.cc:137:32: error: 'struct node' has no member named 'son'
         for (int i = 0; i < h->son.size(); i++)
                                ^~~
/in/foo.cc:138:31: error: 'struct node' has no member named 'son'
             ins += calarea(h->son[i]->tri);
                               ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:184:34: error: 'struct node' has no member named 'son'
         for(int i = 0; i < head->son.size(); i++)
                                  ^~~
/in/foo.cc:186:32: error: 'struct node' has no member named 'son'
             t += calarea(head->son[i]->tri);
                                ^~~