[Leetcode] Intersection of Two Linked Lists

class Solution {
public:
ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
if (headA == NULL || headB == NULL)    return NULL;
int lenA = 0;
int lenB = 0;
ListNode *curA = headA;
ListNode *curB = headB;
while (curA->next) {
lenA++;
curA = curA->next;
}
while(curB->next) {
lenB++;
curB = curB->next;
}

//lenA++;
//lenB++;
if (curA != curB)    return NULL;

int i;
if (lenA > lenB) {
for(i = lenA-lenB; i; i--)
headA = headA->next;
}
else {
for(i = lenB-lenA; i; i--)
headB = headB->next;
}
for (i = 0; i <= min(lenA, lenB); i++) {
if (headA == headB)
return headA;
headA = headA->next;
headB = headB->next;
}
return NULL;
}
};