LeetCode之Intersection of two linked list不同方法

class Solution {
public:
    ListNode* reverseList(ListNode* head){
        if(!head||!head->next)
            return head;
        ListNode* node=head,*last=NULL;
        while(node){
            ListNode* tmp=node->next;
            node->next=last;
            last=node;
            node=tmp;
        }
        return last;
    }
    int getLength(ListNode* head){
        ListNode* node=head;
        int count=0;
        while(node){
            count++;
            node=node->next;
        }
        return count;
    }
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
        if(!headA||!headB)
            return NULL;
        int bLen=getLength(headB),aLen=getLength(headA);
        ListNode* aLast=reverseList(headA);
        ListNode* node=headB;
        while(node->next){
            node=node->next;
        }
        if(node!=headA){
            reverseList(aLast);
            return NULL;
        }
        int reverseLen=getLength(headB);
        int x2=(reverseLen+bLen-aLen)/2;
        reverseList(aLast);
        int count=0;
        node=headB;
        while(node&&count<x2){
            node=node->next;
            count++;
        }
        return node;
    }
};