算法题-链表反转

题目

将单链表的链接顺序反转过来
例：
输入：1→2→3→4→5 
输出：5→4→3→2→1

迭代方式

public ListNode iterate(ListNode head){ListNode prev = null;ListNode next;ListNode curr = head;while(curr!=null){next = curr.next;curr.next = prev;prev = curr;curr = next;}return prev;}

递归方式

public ListNode recursion(ListNode node){if(node == null || node.next == null){return node;}ListNode newNode = recursion(node.next);node.next.next = node;node.next = null;return newNode;
}