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;
        }else if(pHead2==null){
            return pHead1;
        }
        ListNode r = (pHead1.val<=pHead2.val? pHead1:pHead2);
        ListNode p =(pHead1.val>pHead2.val? pHead1:pHead2);
        ListNode s = r,t = s.next;
        while(t!=null && p!=null){
            if (t.val>p.val){
                t = p;
                p = s.next;
                s.next = t;            
            }
            else{
                s = t;
                t = t.next;
            }
        }
        if(t==null){
            s.next = p;
        }
        return r;
    }
}