面试之路（21）-链表的倒序实现

链表的倒序实现

思路分析：

java代码：

stack实现：

class ListNode{
int key;
ListNode next;
}
void reverseStack(ListNode head){
Stack st = new Stack();
while(head != null){
st.push(head);
head =head.next;
}
while(!st.isEmpty()){
head = (ListNode) st.pop();
System.out.println(head.key+"");
}
}

递归实现

class ListNode{
int key;
ListNode next;
}
void reverse(ListNode head){
if(head != null){
if(head.next != null){
reverse(head.next);
}
System.out.println(head.key+"");
}
}