合并两个排序的链表

输入两个单调递增的链表，输出两个链表合成后的链表，当然我们需要合成后的链表满足单调不减规则。

/*public class ListNode {    int val;    ListNode next = null;    ListNode(int val) {        this.val = val;    }}*/public class Solution {    public ListNode Merge(ListNode list1, ListNode list2) {ListNode root  = null ;ListNode node = null ; ListNode p = list1; ListNode q = list2 ;while(p != null || q != null){while(p != null && (q == null || p.val <= q.val)){if(root == null){root = p ; node = p ; }else{node.next = p ; node = p ; }p = p.next ; }while(q != null && (p == null || q.val < p.val)){if(root == null){root = q ; node = q ; }else{node.next = q ; node = q ; }//System.out.println(node.val);q = q.next ; }}return root ; }}