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class Solution {
public:
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
        int countA = 0;
        int countB = 0;
        ListNode * tmpA = headA;
        ListNode * tmpB = headB;
        while(NULL != tmpA)
        {
            countA++;
            tmpA = tmpA->next;
        }
        while(NULL != tmpB)
        {
            countB++;
            tmpB = tmpB->next;
        }
        int move = 0;
        if (countA > countB)
        {
            while (move < countA - countB)
            {
                headA = headA->next;
                move++;
            }
        }
        else
        {
            while (move < countB - countA)
            {
                headB = headB->next;
                move++;
            }
        }
        while (headA != headB)
        {
            headA = headA->next;
            headB = headB->next;
        }
        return headA;
    }
};