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 <iostream>
#include <stack>

class Solution {
public:
    ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
		if (pHead1 == nullptr || pHead2 == nullptr)
			return nullptr;

        stack<ListNode*> stackA;
		stack<ListNode*> stackB;

		ListNode* pNode1 = pHead1;
		ListNode* pNode2 = pHead2;
		while (pNode1 != nullptr) {
			stackA.push(pNode1);
			pNode1 = pNode1->next;
		}
		while (pNode2 != nullptr) {
			stackB.push(pNode2);
			pNode2 = pNode2->next;
		}

		ListNode* FirstCommonNode = nullptr;
		while (!stackA.empty() && !stackB.empty() && stackA.top() == stackB.top()) {
			FirstCommonNode = stackA.top();
			stackA.pop();
			stackB.pop();
		}

		return FirstCommonNode;
    }
};