合并两个有序链表
将两个升序链表合并为一个新的 升序 链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。
输入：l1 = [1,2,4], l2 = [1,3,4]
输出：[1,1,2,3,4,4]

package TOP21_30;import Util.ListNode;import java.util.ArrayList;
import java.util.List;//合并两个有序链表
//将两个升序链表合并为一个新的 升序 链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。
//输入：l1 = [1,2,4], l2 = [1,3,4]
//输出：[1,1,2,3,4,4]
public class Top25 {//数组排序public static ListNode mergeTwoLists2(ListNode list1, ListNode list2) {List<ListNode> nodeList = new ArrayList<>();ListNode res = new ListNode(0);while (list1 != null) {nodeList.add(list1);list1 = list1.next;}while (list2 != null) {nodeList.add(list2);list2 = list2.next;}nodeList.sort((s1, s2) -> (s1.val - s2.val));for (int i = 0; i < nodeList.size(); i++) {ListNode node = nodeList.get(i);if (i == 0) {res.next = node;}if (i <= nodeList.size() - 2) {node.next = nodeList.get(i + 1);}if (i == nodeList.size() - 1) {node.next = null;}}return res.next;}// 双指针public static ListNode mergeTwoLists(ListNode list1, ListNode list2) {ListNode res = new ListNode(0), cur = res;while (list1 != null && list2 != null) {if (list1.val < list2.val) {cur.next = list1;list1 = list1.next;} else {cur.next = list2;list2 = list2.next;}cur = cur.next;}// 一个到头了if (list1 == null) {cur.next = list2;}if (list2 == null) {cur.next = list1;}return res.next;}public static void main(String[] args) {int[] num1 = {1, 5, 7, 9};int[] num2 = {2, 3, 6, 8};ListNode list1 = ListNode.setNodes(0, num1);ListNode list2 = ListNode.setNodes(0, num2);ListNode res = mergeTwoLists(list1, list2);ListNode.printListData(res);}
}

harryptter / LeetcodeTop100 · GitCode