Reverse a singly linked list.
Hint:A linked list can be reversed either iteratively or recursively. Could you implement both?
反转一个单一的链表

算法分析

Java代码

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode reverseList(ListNode head) {
            ListNode pre = null;
            ListNode current = head;
            
            while(current != null) {
                ListNode nextTemp = current.next;
                current.next = pre;
                pre = current;
                current = nextTemp;
            }
            return pre;
    }
}

参考

LeetCode