python--Python list轉爲鏈表

代碼即註釋如下

import sys
import json


class ListNode:
    """
    定義一個節點,包括value 和next指針,指向下一個node
    """

    def __init__(self, x):
        self.val = x
        self.next = None


def stringToIntegerList(input):
    return json.loads(input)


def stringToListNode(input):
    # Generate list from the input
    numbers = stringToIntegerList(input)

    # Now convert that list into linked list
    dummyRoot = ListNode(0)
    ptr = dummyRoot  # 3.複製一個實例對象(可變變量,ptr屬性變,dummyRoot 也會變,ptr賦值變,dummyRoot 不變)
    for number in numbers:  # [1,2,3]
        ptr.next = ListNode(number)  # 4. ListNode(val =0 ,next=ListNode(val =1 ,next=None))
        ptr = ptr.next  # 5. ptr=ListNode(val=1 ,next=None)
        # 第一層: dummyRoot: ListNode(val =0 ,next=ListNode(val =1 ,next=None))
        # 第二層: dummyRoot: ListNode(val =0 ,next=ListNode(val =1 ,next=ListNode(val =2 ,next=None)))

    ptr = dummyRoot.next  # 最後 ptr在dummyRoot的基礎上去掉了val=0
    return ptr


def prettyPrintLinkedList(node):
    while node and node.next:
        print(str(node.val) + "->", end='')
        node = node.next

    if node:
        print(node.val)
    else:
        print("Empty LinkedList")


def main():
    def readlines():
        for line in sys.stdin:
            yield line.strip('\n')

    lines = readlines()  # 1.獲取一個生成器
    while True:
        try:
            line = next(lines)  # 2.暫停代碼, 通過next()獲取生成輸入的字符串列表
            node = stringToListNode(line)
            prettyPrintLinkedList(node)
        except StopIteration:
            break


if __name__ == '__main__':
    main()

pt結構如下圖