466 链表节点计数

原题网址： http://www.lintcode.com/zh-cn/problem/count-linked-list-nodes/

计算链表中有多少个节点.

您在真实的面试中是否遇到过这个题？ 

Yes

样例

给出 1->3->5, 返回 3.

标签 

链表

 

/**
 * Definition of singly-linked-list:
 * class ListNode {
 * public:
 *     int val;
 *     ListNode *next;
 *     ListNode(int val) {
 *        this->val = val;
 *        this->next = NULL;
 *     }
 * }
 */

class Solution {
public:
    /**
     * @param head: the first node of linked list.
     * @return: An integer
     */
    int countNodes(ListNode * head) {
        // write your code here
        if (head==NULL)
        {
            return 0;
        }
        else
        {
            ListNode *p=head;
            int total=1;
            while (p->next!=NULL)
            {
                total++;
                p=p->next;
            }
            return total;
        }
    }
};