判断俩单链表是否相交

AC 代码 总的来说,单链表分为两种 无环单链表,有环单链表,判断单链表相交则可转化为 俩无环单链表是否相交,俩有环单链表是否相交,而一条有环一条无环一定不可能相交!

class ChkIntersection {
    ListNode * findLoopNode(ListNode* head,int &len){//查找入环借点,若无环返回NULL;若无环即得到无环单链表长度
        ListNode *quick=NULL,*slow=head->next;
        ++len;
        if(!slow)
            return NULL;
        quick = slow->next;
        ++len;
        while (true) {
            if(!quick||!slow)
                return NULL;
            if(quick == slow)
                break;
            slow = slow->next;
            quick = quick->next;
            ++len;
            if(!quick)
                return NULL;
            quick = quick->next;
            ++len;
        }
        quick = head;
        while (quick!=slow) {
            quick = quick->next;
            slow = slow->next;
        }
        return quick;
    }
    ListNode *walknums(ListNode *head,int nums){//让长的链表先走nums 步
        while (nums--) {
            head = head->next;
        }
        return head;
    }
public:
    bool chkInter(ListNode* head1, ListNode* head2, int adjust0, int adjust1) {
        if(!head1||!head2)
            return false;
        int len1 = 0,len2 = 0;
        ListNode * loop1 = findLoopNode(head1,len1), *loop2 = findLoopNode(head2,len2);
        if((loop1==NULL&&loop2)||(loop1&&loop2==NULL))//一个有环 ,一个无环
            return false;
        else if(loop1==NULL&&loop2==NULL){//俩个都无环
            if(len1>=len2)
                head1 = walknums(head1,len1-len2);
            else
                head2 = walknums(head2,len2-len1);
            while (head1&&head2) {
                if(head2==head1)
                    return true;
                head1 = head1->next;
                head2 = head2->next;
            }
            return false;
        }else{//俩有环单链表相交
            if(loop1==loop2)
                return true;
            else{
                ListNode * p =loop1->next;
                while (p!=loop1) {
                    if(p==loop2)
                        return true;
                    p = p->next;
                }
                return false;
            }
        }
    }
};