# ---
# title: 328. Odd Even Linked List
# id: problem328
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Linked List
# link: <https://leetcode.com/problems/odd-even-linked-list/description/>
# hidden: true
# ---
# 
# 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->NULL
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: 2->1->3->5->6->4->7->NULL
#     Output:2->3->6->7->1->5->4->NULL
#     
# 
# 
# 
# **Constraints:**
# 
#   * 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 ...
#   * The length of the linked list is between `[0, 10^4]`.
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
