這道題沒啥好說的就是一個普通的鏈表遍歷並且計數

Java:

/**
 * Definition for ListNode.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int val) {
 *         this.val = val;
 *         this.next = null;
 *     }
 * }
 */


public class Solution {
    /*
     * @param head: the first node of linked list.
     * @return: An integer
     
 
*/
    public int countNodes(ListNode head) {
        int i = 0;
        while(head!=null && ++i>0)
            head = head.next;
        return i;
    }
}

"""
Definition of ListNode
class ListNode(object):

    def __init__(self, val, next=None):
        self.val = val
        self.next = next
"""


class Solution:
    """
    @param: head: the first node of linked list.
    @return: An integer
    """
    def countNodes(self, head):
        i = 0
        while head is not None:
            head = head.next
            i = i+1
        return i
        

鏈表節點計數（入門）