题解 | #两个链表的第一个公共结点#

// 不太聪明的亚子，用了栈
/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) :
            val(x), next(NULL) {
    }
};*/
class Solution {
public:
    ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
        if(!pHead1 || !pHead2)
        {
            return nullptr;
        }
        stack<ListNode*> sta1;
        stack<ListNode*> sta2;

        while(pHead1)
        {
            sta1.push(pHead1);
            pHead1 = pHead1->next;
        }
        while(pHead2)
        {
            sta2.push(pHead2);
            pHead2 = pHead2->next;
        }
        ListNode* node = nullptr;
        while(!sta1.empty() && !sta2.empty())
        {
            if(sta1.top() == sta2.top())
            {
                node = sta1.top();
            }
            sta1.pop();
            sta2.pop();
        }
        return node;
    }
};