题解 | #合并两个排序的链表#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param pHead1 ListNode类
     * @param pHead2 ListNode类
     * @return ListNode类
     */
    public ListNode Merge (ListNode pHead1, ListNode pHead2) {
        //操作指针
        ListNode cur  = new ListNode(-1);
        //用来返回的链表
        ListNode resNode = cur;

        //依次对比节点，进行拼接
        while (pHead1 != null && pHead2 != null) {
            if (pHead1.val <= pHead2.val) {
                cur.next  = pHead1;
                pHead1 = pHead1.next;
                cur = cur.next;

            } else if (pHead2.val <= pHead1.val) {
                cur.next  = pHead2;
                pHead2 = pHead2.next;
                cur = cur.next;
            }

        }

        //剩下的节点直接拼接
        if (pHead1 != null) {
            cur.next = pHead1;

        }

        if (pHead2 != null) {
            cur.next = pHead2;

        }

        return resNode.next;
    }
}