两个链表的第一个公共结点

题目描述

/*
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 NULL;
ListNode *p1=pHead1,*p2=pHead2;
while(p1&&p1!=p2){
p2=pHead2;
while(p2&&p2!=p1) p2=p2->next;
if(p2) break;
else p1=p1->next;
}
return p1;
}
};