构造一个递增有序的正整数链表,实现链表分解为一个奇数表和一个偶数表,之后再将两个链表合并一个递减链表。的思想怎么写
时间: 2024-10-19 17:13:32 浏览: 14
首先,我们可以构建一个递增有序的正整数链表,这通常通过循环或迭代的方式创建,节点包含一个整数值和指向下一个节点的指针。例如:
```python
class ListNode:
def __init__(self, val=0, next=None):
self.val = val
self.next = next
def build_sorted_list(nums):
head = None
tail = None
for num in nums:
new_node = ListNode(num)
if not head:
head = tail = new_node
else:
tail.next = new_node
tail = new_node
return head
```
接下来,我们需要将这个链表分解为奇数表和偶数表。我们可以在遍历链表的同时,根据节点值的奇偶性将它们分别添加到对应的链表中:
```python
def split_linked_list(head):
odd_head = even_head = None
current = head
while current:
if current.val % 2 == 0:
current.next = even_head
even_head = current
else:
current.next = odd_head
odd_head = current
current = current.next if current else None
return odd_head, even_head
```
最后,合并这两个链表并形成递减链表。这可以通过先将偶数链表反转,然后交替链接奇数和偶数节点来实现:
```python
def merge_and_descent(odd, even):
odd_tail = odd
even_tail = even
merged_head = merged_tail = ListNode()
while odd and even:
merged_tail.next = ListNode(even.val) if even.val < odd.val else ListNode(odd.val)
merged_tail = merged_tail.next
odd = odd.next if odd else None
even = even.next if even else None
if odd:
merged_tail.next = odd
elif even:
merged_tail.next = ListNode(even.val)
merged_tail.next = None # 结束标志
return merged_head.next
```
现在,你可以按照这个思路依次创建链表、分割它,然后合并得到最终的递减链表。记得对输入的`nums`列表做适当的处理,比如检查是否为空,以及元素是否都是正整数。
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