庸题目,看了半天才看懂
1.小于x部分的链表按照原始顺序记为before
2.大于等于x部分的链表按照原始顺序记为after
3.before和after进行拼接
class Solution {
public ListNode partition(ListNode head, int x) {
ListNode dummy1 = new ListNode(0), dummy2 = new ListNode(0);
ListNode node1 = dummy1, node2 = dummy2;
while(head != null){
if(head.val < x){
node1.next = head;
head = head.next;
node1 = node1.next;
node1.next = null;
}else {
node2.next = head;
head = head.next;
node2 = node2.next;
node2.next = null;
}
}
node1.next = dummy2.next;
return dummy1.next;
}
}