反转单链表LeetCode206

LeetCode206
题目要求：反转单链表

	private ListNode reverseList(ListNode head){
        if(head==null)return null;
        ListNode next = head.next;
        head.next = null;
        ListNode nnext = null;
        while(next!=null){
            nnext = next.next;
            next.next = head;
            head = next;
            next = nnext;
        }
        return head;
    }

思路全在图里面，配合代码和图加上自己模拟一遍，就懂了。