160.相交链表

🚌set实现

class Solution {
public:
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
        set<ListNode*> st;
        while(headA) {
            st.insert(headA);
            headA = headA->next;
        }
        while(headB) {
            if(st.count(headB))
                return headB;
            headB = headB->next;
        }
        return nullptr;
    }
};