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 hair = new ListNode(0), p = pHead1, q = pHead2, cur = hair;
        while (p != null && q != null) {
            if (p.val < q.val) {
                cur.next = p;
                p = p.next;
            } else {
                cur.next = q;
                q = q.next;
            }
            cur = cur.next;
        }
        if (p != null) cur.next = p;
        if (q != null) cur.next = q;
        return hair.next;
    }
}