3. 從尾到頭打印鏈表
題目描述
輸入一個鏈表,按鏈表值從尾到頭的順序返回一個ArrayList。
題目鏈接
Java實現:
/**
* @Classname Solution.replaceSpace
* @Date 2019/5/29 11:07
* @Created by 超
*/
/**
* public class ListNode {
* int val;
* ListNode next = null;
*
* ListNode(int val) {
* this.val = val;
* }
* }
*
*/
//解法1: 遞歸
import java.util.ArrayList;
public class Solution {
ArrayList<Integer> list = new ArrayList<Integer>();
public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
if (listNode != null) {
this.printListFromTailToHead(listNode.next);
list.add(listNode.val);
}
return list;
}
}
//解法2: 棧
import java.util.Stack;
import java.util.ArrayList;
public class Solution {
public ArrayList<Integer> printListFromTailToHead(ListNode listNode) {
Stack<Integer> stack = new Stack<Integer>();
while (listNode != null) {
stack.push(listNode.val);
listNode = listNode.next;
}
ArrayList<Integer> list = new ArrayList<Integer>();
while (! stack.isEmpty()) {
list.add(stack.pop());
}
return list;
}
}
不足之處歡迎批評討論!