题解 | #两个链表的第一个公共结点#

/*
struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
			val(x), next(NULL) {
	}
};*/
#include <cstddef>
class Solution {
public:
    ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
		if (pHead1 == NULL || pHead2 == NULL)
		{
			return NULL;
		}

		ListNode * pNode1 = pHead1;
        set<ListNode *> set_tmp;
		while (pNode1 != NULL)
		{
			set_tmp.insert(pNode1);
			pNode1 = pNode1->next;
		}

		ListNode * pNode2 = pHead2;
		while (pNode2 != NULL)
		{
			if (set_tmp.find(pNode2) != set_tmp.end())
			{
				return pNode2;
			}
			pNode2 = pNode2->next;
		}

		return NULL;
    }
};