LeetCode 0328 - Odd Even Linked List
LeetCode 0328 - Odd Even Linked List
Reck Zhang
发布于 2021-08-11 11:18:54
发布于 2021-08-11 11:18:54
文章被收录于专栏：Reck Zhang
Odd Even Linked List
Desicription
Given a singly linked list, group all odd nodes together followed by the even nodes. Please note here we are talking about the node number and not the value in the nodes.
You should try to do it in place. The program should run in O(1) space complexity and O(nodes) time complexity.
Example 1:
Input: 1->2->3->4->5->NULL
Output: 1->3->5->2->4->NULLExample 2:
Input: 2->1->3->5->6->4->7->NULL
Output: 2->3->6->7->1->5->4->NULLNote:
- The relative order inside both the even and odd groups should remain as it was in the input.
- The first node is considered odd, the second node even and so on …
Solution
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* oddEvenList(ListNode* head) {
if(head == nullptr) {
return nullptr;
}
auto odd = head;
auto even = head->next;
auto evenHead = even;
while(even != nullptr && even->next != nullptr) {
odd->next = odd->next->next;
even->next = even->next->next;
odd = odd->next;
even = even->next;
}
odd->next = evenHead;
return head;
}
};本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
原始发表：2019-05-23，如有侵权请联系 cloudcommunity@tencent.com 删除
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