Lc21_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。 
//
// 
//
// 示例： 
//
// 输入：1->2->4, 1->3->4
//输出：1->1->2->3->4->4
// 
// Related Topics 链表

package leetcode.editor.cn;

import com.example.demo.ArrayConvertLinkedList;
import com.example.demo.ListNode;

//Java：合并两个有序链表
public class P21MergeTwoSortedLists{
    public static void main(String[] args) {
        Solution solution = new P21MergeTwoSortedLists().new Solution();
        // TO TEST
        int[] array = {1,2,4};
        int[] array1 = {1,3,4};
        ListNode head = ArrayConvertLinkedList.arrayToNode(array);
        ListNode head1 = ArrayConvertLinkedList.arrayToNode(array1);
        ListNode res = solution.mergeTwoLists(head,head1);
        ArrayConvertLinkedList.printNode(res);
    }
    //leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
       if(l1==null){
           return l2;
       }else if(l2==null){
           return l1;
       }else if(l1.val<=l2.val){
           l1.next = mergeTwoLists(l1.next,l2);
           return l1;
       }else{
           l2.next = mergeTwoLists(l1,l2.next);
           return l2;
       }
    }
}
//leetcode submit region end(Prohibit modification and deletion)

}