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) {
        // write code here
        if(pHead1==null)
            return pHead2;
        if(pHead2==null)
            return pHead1;
        
        ListNode a=pHead1;
        ListNode b=pHead2;   
        ListNode pHead3=new ListNode(-1);
        ListNode c=pHead3;
        while(a!=null&b!=null){
            if(a.val<=b.val) {
                c.next=a;
                a=a.next;
            }
            else{
                c.next=b;
                b=b.next;
            }
            System.out.println(c.val);
            c=c.next;

        }
        if(a==null&&b!=null)
            c.next=b;
        if(b==null&&a!=null) c.next=a;

        return pHead3.next;
    }
}