将一个数组12 3赋值给一个单链表

以下是Python代码实现：

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next
        
arr = [1, 2, 3]
head = ListNode()
cur = head

for num in arr:
    cur.next = ListNode(num)
    cur = cur.next

head = head.next # 去掉头结点

# 打印链表
while head:
    print(head.val, end=' ')
    head = head.next

输出：

1 2 3