/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode *findFirstCommonNode(ListNode *headA, ListNode *headB) {
        //使用hash 去做
       int a[10000000];
        ListNode *l=headA,*r=headB;
        while(l!=NULL){
            a[(int&)l%973311]++;
            l=l->next;
        }
        while(r!=NULL){
            if(a[(int&)r%973311]!=0)return r;
            r=r->next;
        }
        return NULL;

    }
};