BOJ-14725

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>

using namespace std;

struct Node{
  map<string, Node*> child;
  map<string, Node*>::iterator iter;

  void insert(vector<string> v, int idx) {
    if (idx == v.size()) return;
    string ss = v[idx];
    iter = child.find(ss);
    if (iter != child.end()) iter->second->insert(v, idx + 1);
    else {
      Node* n = new Node;
      child.insert({ ss,n });
      n->insert(v, idx + 1);
    }
  }

  void print(int idx) {
    if (child.empty()) return;
    for (auto it = child.begin(); it != child.end(); it++) {
      for (int i = 0; i < idx; i++)
        cout << "--";
      cout << it->first << '\n';
      it->second->print(idx + 1);
    }
  }
};

Node tmp;

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL); cout.tie(NULL);
  
  int num, val;
  Node* root = new Node;
  string ss;
  cin >> num;
  for (int i = 0; i < num; i++) {
    cin >> val;
    vector<string> v;
    for (int j = 0; j < val; j++) {
      cin >> ss;
      v.push_back(ss);
    }
    root->insert(v, 0);
  }
  root->print(0);
  return 0;
}