#include <iostream>
#include <string>

using namespace std;

// A structure that stores information about a person
struct Person {
  string firstName;
  string lastName;
  int age;
  Person *next;
};

// A function that prints a one-way list with a given start
void printList(Person *head) {
  // Check if the list is not empty
  if (head == NULL) {
    cout << "Lista jest pusta" << endl;
    return;
  }

  // Printing each list item
  cout << "Lista: " << endl;
  Person *curr = head;
  while (curr != NULL) {
    cout << curr->firstName << " " << curr->lastName << ", wiek: " << curr->age << endl;
    curr = curr->next;
  }
}

// A function that adds new people to the list before every second person older than the penultimate person on the list
void addPersons(Person *head) {
  // Check if the list has at least 3 elements
  if (head == NULL || head->next == NULL || head->next->next == NULL) {
    cout << "The list is too short to perform this operation" << endl;
    return;
  }

// Load data of new people
  cout << "Enter the data of new people (name, surname, age):" << endl;
  Person *prev = head->next;
  Person *curr = head->next->next;
  while (curr != NULL) {
    if (curr->age > prev->age) {
      // Tworzenie nowej osoby
      Person *newPerson = new Person();
      cin >> newPerson->firstName >> newPerson->lastName >> newPerson->age;
      newPerson->next = curr;

      // Adding a new person to the list
      prev->next = newPerson;

      // Movement of pointers
      prev = curr;
      curr = curr->next;
    } else {
      prev = curr;
      curr = curr->next;
      if (curr != NULL) {
        prev = curr;
        curr = curr->next;
      }
    }
  }
}