# week05_02_chap04_06.py

class Node:
    def __init__(self):
        self.data = None
        self.link = None


def print_nodes(start):
    current = start
    if current is None:  # 출력할 노드가 없으면
        return

    print(current.data, end=' ')
    while current.link is not None:
        current = current.link  # 가르키는 대상 변경(증가)
        print(current.data, end=' ')
    print()


def insert_node(find_data, insert_data):
    global head, current, pre

    if head.data == find_data:
        node = Node()
        node.data = insert_data
        node.link = head
        head = node
        return

    current = head
    while current.link is not None:
        pre = current
        current = current.link
        if current.data == find_data:
            node = Node()
            node.data = insert_data
            node.link = current
            pre.link = node
            return

    node = Node()
    node.data = insert_data
    current.link = node


head, current, pre = None, None, None
data_array = ["다현", "정연", "쯔위", "사나", "지효"]

if __name__ == "__main__":
    node = Node()
    node.data = data_array[0]
    head = node

    for i in range(1, len(data_array)):
    #for data in data_array[1:]:
        pre = node
        node = Node()
        node.data = data_array[i]
        #node.data = data
        pre.link = node

    print_nodes(head)

    insert_node("다현", "화사")
    print_nodes(head)

    insert_node("사나", "솔라")
    print_nodes(head)

    insert_node("이나", "문별")
    print_nodes(head)