The first common node of the two linked lists of "Jianzhi offer"

Title Description

Enter two linked lists , Find their first common node .

 

There are common nodes with the same length , The first time I traverse ;
There are no public nodes , Go to the end NULL meet , return NULL

Different lengths have common nodes , The difference comes out the first time , Go to the public node together for the second time ;
No public , The second time together to the end NUL

/*
struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
			val(x), next(NULL) {
	}
};*/
class Solution {
public:
	ListNode* FindFirstCommonNode(ListNode* pHead1, ListNode* pHead2) {
		ListNode *p1 = pHead1;
		ListNode *p2 = pHead2;
		while (p1 != p2){
			p1 = (p1 == nullptr ? pHead1 : p1->next);
			p2 = (p2 == nullptr ? pHead2 : p2->next);
		}
		return p1;
	}
};