public ListNode getIntersectionNode(ListNode headA, ListNode headB) {

        if(headA==null||headB==null)

        	return null;

        int lengthA=0,lengthB=0;

        ListNode tempA=headA,tempB=headB;

    	while(tempA!=null){

    		tempA=tempA.next;

    		lengthA++;

        }

    	while(tempB!=null){

    		tempB=tempB.next;

    		lengthB++;

        }

    	if(lengthB>lengthA){

    		tempA=headA;

    		headA=headB;

    		headB=tempA;

    		int temp=lengthA;

    		lengthA=lengthB;

    		lengthB=temp;

    	}

    	int length=lengthA-lengthB;

    	while(length-->0)

    		headA=headA.next;

    	while(headA!=null){

    		if(headA==headB)

    			return headA;

    		headA=headA.next;

    		headB=headB.next;

    	}

    	return headA;

    }