Java实现从尾到头打印链表的实例分析

public class ListNode {
    int val;
    ListNode next = null;
    ListNode(int val){
      this.val = val;
    }
  }

public static Stack<Integer> printListReverse_Stack(ListNode listNode){
    Stack<Integer> stack = new Stack<Integer>();
    if(listNode != null){
      ListNode p = listNode;
      while(p != null){
        stack.add(p.val);
        p = p.next;
      }
    }
    return stack;
  }

public static ArrayList<Integer> printListFromTailToHead(ListNode listNode){//表头也存储元素
    ArrayList<Integer> print = new ArrayList<Integer>();
    if(listNode == null){
      return print;
    }
    int add = 0;
    ListNode p = listNode;
    while(p != null){
      print.add(0, p.val);
      p = p.next;
    }
    return print;
  }

public ArrayList<Integer> printListReversely_Recursively(ListNode listNode){
    ArrayList<Integer> print = new ArrayList<Integer>();
    if(listNode == null){
      return print;
    }
    print.addAll(printListReversely_Recursively(listNode.next));
    print.add(listNode.val);
    return print;
  }