算法练习(13) - 反转链表中间某段

class Solution {
    public ListNode reverseBetween(ListNode head, int left, int right) {
        ListNode dummyHead = new ListNode(0);
        dummyHead.next = head;

        ListNode g  = dummyHead;
        ListNode p  = dummyHead;

        for(int i =0;i<left-1;i++){
            g = g.next;
            p = p.next;
        }
        p = p.next;

        for(int i = left;i < right;i++){
            // 将p的next缓存一下
            ListNode removed = p.next;
            // p一直在left节点上,指向next.next
            p.next = p.next.next;
            // 将缓存值头插到g.next
            removed.next = g.next;
            // 将缓存值尾插到g
            g.next = removed;
        }
        return dummyHead.next;
    }
}