两个链表的第一个公共结点

 1 　　public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2){
 2         int count1 = 0, count2 = 0;
 3         ListNode node1 = pHead1, node2 = pHead2;
 4         while(node1!=null){
 5             count1++;
 6             node1 = node1.next;
 7         }
 8         while(node2!=null){
 9             count2++;
10             node2 = node2.next;
11         }
12         if(node1!=node2)
13             return null;
14         ListNode n1 = pHead1, n2 = pHead2;
15         if(count1>count2){
16             for(int i=0;i<count1-count2;i++){
17                 n1 = n1.next;
18             }
19         }
20         else{
21             for(int i=0;i<count2-count1;i++){
22                 n2 = n2.next;
23             }
24         }
25         while(n1!=n2){
26             n1 = n1.next;
27             n2 = n2.next;
28         }
29         return n1;
30     }