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【LeetCode】21. Merge Two Sorted Lists

题目:

  Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

思路:比较每个列表的第一个元素。 合并小的添加到列表中。 最后,当其中一个是空的,只需将它附加到合并后的列表,因为它已经排序。

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode head=new ListNode(-1);
        ListNode addNode=head;
        while(l1!=null&&l2!=null){
            if(l1.val<l2.val){
                addNode.next=l1;
                l1=l1.next;
            }else{
                addNode.next=l2;
                l2=l2.next;
            }
            addNode=addNode.next;
        }
        if(l1==null) addNode.next=l2;
        if(l2==null) addNode.next=l1;
        return head.next;
    }
}

 

【LeetCode】21. Merge Two Sorted Lists