Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.
You should preserve the original relative order of the nodes in each of the two partitions.
For example,
Given 1->4->3->2->5->2
and x = 3,
return 1->2->2->4->3->5
.
准备左右两个链表,左链表放比x小的节点,右链表放大于等于x的节点,最后两个链表再进行连接。
public ListNode partition(ListNode head, int x) {
ListNode left = new ListNode(-1), tmpL = left;
ListNode right = new ListNode(-1), tmpR = right;
while (head != null) {
if (head.val < x) {
left.next = head;
left = left.next;
} else {
right.next = head;
right = right.next;
}
head = head.next;
}
left.next = tmpR.next;
right.next = null;
return tmpL.next;
}