剑指offer-问题5

向右看齐 2022-05-10 12:36 207阅读 0赞

package offer;
    
    import java.util.Stack;
    
    /**
     * offer interview 05
     */
    public class Test05 {
        public static class ListNode{
            int val;
            ListNode next;
    
            public ListNode(){
    
            }
    
            public ListNode(int val){
                this.val = val;
            }
        }
    
        /**
         * method 1
         * @param root
         */
        public static void printListInverselyUsingIteration(ListNode root){
            Stack<ListNode> stack = new Stack<>();
            while (root != null){
                stack.push(root);
                root = root.next;
            }
    
            ListNode tmp;
    
            while (!stack.isEmpty()){
                tmp = stack.pop();
                System.out.print(tmp.val + " ");
            }
            System.out.println();
        }
    
        /**
         * method 2
         * @param root
         */
        public static void printListInverselyUsingRecursion(ListNode root){
           if (root != null){
               printListInverselyUsingRecursion(root.next);
               System.out.print(root.val + " ");
           }
        }
    
    
    
        public static void main(String[] args){
            ListNode root = new ListNode(1);
            root.next = new ListNode(2);;
            root.next.next = new ListNode(3);
            root.next.next.next = new ListNode(4);
            root.next.next.next.next = new ListNode(5);
    
            printListInverselyUsingIteration(root);
            System.out.println("==========");
            printListInverselyUsingRecursion(root);
    
        }
    
    
    
    }