LeetCode 328 Odd Even Linked List

 

用到了两个dummy node。

public class Solution {
  public ListNode oddEvenList(ListNode head) {
    // Write your solution here
    if (head == null || head.next == null) {
        return head; 
    }
        ListNode odd = new ListNode(0);
    ListNode oddTail = odd;
    ListNode even = new ListNode(0);
    ListNode evenTail = even;
    ListNode cur = head;
    while (cur != null) {
        if (cur.value % 2 == 1) {
          oddTail.next = cur;
        oddTail = oddTail.next;
      } else {
           evenTail.next = cur;
        evenTail = evenTail.next;
      }
      cur = cur.next;
    }
    oddTail.next = even.next;
    evenTail.next = null;
    return odd.next;
  }
}