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:    int GetLength(ListNode* head){int len = 0;        while(head != NULL){            len++;            head = head->next;        }        return len;    }        ListNode* FindFirstCommonNode( ListNode *pHead1, ListNode *pHead2) {int len1 = GetLength(pHead1);        int len2 = GetLength(pHead2);        if(len1 < len2){            ListNode* temp = pHead2;            pHead2 = pHead1;            pHead1 = temp;            int tempInt = len1;            len1 = len2;            len2 = tempInt;        }        for(int i = 0; i < len1 - len2; i++)            pHead1 = pHead1->next;        for(int i = 0; i < len2; i++)            if(pHead1 == pHead2)            return pHead1;            else{            pHead1 = pHead1->next;            pHead2 = pHead2->next;        }        return NULL;}};