LeetCode 160. 相交链表（）

20230321 顺利通过
20230411 顺利通过
原题解

题目

约束

题解

方法一

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

方法二

class Solution {
public:
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
        if (headA == nullptr || headB == nullptr) {
            return nullptr;
        }
        ListNode *pA = headA, *pB = headB;
        while (pA != pB) {
            pA = pA == nullptr ? headB : pA->next;
            pB = pB == nullptr ? headA : pB->next;
        }
        return pA;
    }
};