单向链表逆序输出

实现链表逆序输出

class Solution<T> {

    public void reverse(ListNode<T> head) {
       if (head == null || head.next == null) {
    	   return ;
       }
       ListNode<T> currentNode = head;
       Stack<ListNode<T>> stack = new Stack<>();
       while (currentNode != null) {
    	   stack.push(currentNode);
    	   ListNode<T> tempNode = currentNode.next;
           // 断开连接
    	   currentNode.next = null; 
    	   currentNode = tempNode;
       }
       
       head = stack.pop();
       currentNode = head;
       
       while (!stack.isEmpty()) {
    	   currentNode.next = stack.pop();
    	   currentNode = currentNode.next;
       }
    }
}

class ListNode<T>{
	T val;
	public ListNode(T val) {
		this.val = val;
	}
	ListNode<T> next;
}