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#include "linked_list.h"

// Returns the value at head
int List::head() {
  // TODO: Implement this method
  if (!m_head) {
    throw "Empty List";
  }
  return m_head->element;
}

// Checks whether the container is empty
bool List::empty() const {
  // TODO: Implement this method
  if (m_size == 0 || !m_head) {
    return true;
  }
  return false;
}

// Returns the number of elements
size_t List::size() const {
  // TODO: Implement this method
  return m_size;
}

// Inserts an element to the head
void List::push_head(int element) {
  // TODO: Implement this method
  Node* newnode = new Node(element);
  newnode->next = m_head;
  m_head = newnode;
  m_size++;
}

// Removes the head element
int List::pop_head() {
  // TODO: Implement this method
  if (!m_head) {
    throw "Empty List";
  }
  Node* temp = m_head;
  m_head = m_head->next;
  int popped = temp->element;
  delete temp;
  m_size--;
  return popped;
}

// Checks whether the container contains the specified element
bool List::contains(int element) const {
  // TODO: Implement this method
  if (!m_head) {
    return false;
  }

  Node* temp = m_head;

  while (temp) {
    if (temp->element == element) {
      return true;
    }
    temp = temp->next;
  }
  return false;
}

// Returns a std::string equivalent of the container
std::string List::to_string() const {
  // TODO: Implement this method
  if (!m_head) {
    return "{}";
  }

  std::string lst1 = "{";
  Node* temp = m_head;

  while (temp) {
    lst1 = lst1 + std::to_string(temp->element);
    temp = temp->next;
    if (temp) {
      lst1 += ", ";
    }
  }
  return lst1 + '}';
}