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) {
	}
};*/
class Solution {
public:
    ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
        if(pHead1 == nullptr || pHead2 == nullptr){
            return nullptr;
        }
        ListNode* p1 = pHead1;
        ListNode* p2 = pHead2;
        
        while(p1 != p2){
            p1 = p1->next;
            p2 = p2->next;
            
            if(p1 == nullptr && p2 == nullptr){
                return nullptr;
            }
            if(p1 == nullptr){
                p1 = pHead2;
            }
            if(p2 == nullptr){
                p2 = pHead1;
            }
            
        }
        
        return p1;
        
    }
};