题解 | #两个链表的第一个公共结点#

/*使用栈思想，注意特殊处理的情况
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==nullptr||pHead2==nullptr) return nullptr;
		vector<ListNode*>stack1,stack2;
        while(pHead1!=nullptr){
			stack1.push_back(pHead1);
			pHead1=pHead1->next;
		}
		while(pHead2!=nullptr){
			stack2.push_back(pHead2);
			pHead2=pHead2->next;
		}
		int i=0;
		while(1){
			if(i==stack1.size()||i==stack2.size()) break;
			if(stack1[stack1.size()-i-1]==stack2[stack2.size()-i-1]){
				i++;
			}
			else{
				return stack1[stack1.size()-i];
			}
			
		}
		return  stack1[stack1.size()-i];
    }
};