在 Python 中的给定位置之前将新元素插入链表的程序
假设我们有一个元素列表；这些元素存储在一个单向链表中。我们还有一个值pos和值val。我们必须在链表的索引pos之前插入val。
因此，如果输入类似于nums=[1,5,3,6,8]pos=3val=7，那么输出将是[1,5,3,7,6,8]
示例
让我们看下面的实现来更好地理解
class ListNode:
def __init__(self, data, next = None):
self.val= data
self.next= next
def make_list(elements):
head = ListNode(elements[0])
for element in elements[1:]:
ptr = head
while ptr.next:
ptr = ptr.next
ptr.next = ListNode(element)
return head
def print_list(head):
ptr = head
print('[', end = "")
while ptr:
print(ptr.val, end = ", ")
ptr = ptr.next
print(']')
def solve(list_head, pos, val):
new = ListNode(val)
if pos == 0:
new.next = list_head
return new
temp = list_head
while temp and pos != 1:
temp = temp.next
pos -= 1
next = temp.next
temp.next= new
return list_head
nums = [1,5,3,6,8]
pos = 3
val = 7
list_head = make_list(nums)
list_head = solve(list_head, pos, val)
print_list(list_head)输入
[1,5,3,6,8], 3, 7输出结果
[1, 5, 3, 7, 6, 8, ]