328. [链表]奇偶链表

328. 奇偶链表

class Solution {
    public ListNode oddEvenList(ListNode head) {
        if(head == null){
            return null;
        }
        ListNode oddStart = head, evenStart = head.next;
        ListNode last = evenStart, ans = oddStart;
        while (oddStart.next != null && oddStart.next.next != null){
            oddStart.next = oddStart.next.next;
            oddStart = oddStart.next;

            evenStart.next = evenStart.next.next;
            evenStart = evenStart.next;
        }
        oddStart.next = last;
        return ans;
    }
}