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) {
        if (pHead1 == null) {
            return pHead2;
        }
        else if (pHead2 == null) {
            return pHead1;
        }
        else if (pHead1.val < pHead2.val) {
            pHead1.next = Merge(pHead1.next, pHead2);
            return pHead1;
        }
        else {
            pHead2.next = Merge(pHead1, pHead2.next);
            return pHead2;
        }
    }
}