尾插法建立单链表（Python版）

习惯了力扣模式，碰到acm模式让手动建立单链表就不会了。记录一下吧。

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next


def createList(nums):  #输入一个数组，返回链表头结点
    prehead = ListNode()
    p = prehead
    for item in nums:
        node = ListNode(item)
        p.next = node
        p = node
    return prehead.next


head = createList([1, 2, 3])
while head:
    print(head.val, end=' ')
    head = head.next