题解 | #反转链表#
反转链表
https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca
JZ24 反转链表
使用栈来对链表进行反转。注意考虑链表为空的情况，并且要记得最后的节点的next要设为null，否则会构成环
import java.util.*;
/*
public class ListNode {
int val;
ListNode next = null;
ListNode(int val) {
this.val = val;
}
}*/
public class Solution {
public ListNode ReverseList(ListNode head) {
if(head == null)
return null;
Stack<ListNode> stack = new Stack<>();
ListNode temp = head;
while(temp != null) {
stack.push(temp);
temp = temp.next;
}
ListNode reverseHead = stack.pop();
ListNode p = reverseHead;
while(!stack.isEmpty()) {
p.next = stack.pop();
p = p.next;
}
p.next = null;
return reverseHead;
}
}
