/* public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; } }*/ public class Solution { // 1-2-3 3-2-1 public ListNode ReverseList(ListNode head) { ListNode fast = head; ListNode pre = null; while (fast != null) { ListNode tempSave = fast.next; fast.next = pre; pre = fast; fast = tempSave; } return pre; } }
采用交换链表节点解决此问题,每一次循环用当前节点链接下一个节点,而这个下一个节点就是我们的前一个节点,最后连成链条以后存储倒pre里,