LF.33.number Of Nodes

Return the number of nodes in the linked list.

Examples

L = null, return 0
L = 1 -> null, return 1
L = 1 -> 2 -> null, return 2

public class Solution {
  public int numberOfNodes(ListNode head) {
    // Write your solution here
    if (head == null) {
        return 0;
    }
    int res = 0;
    ListNode curr = head ;
    while(curr != null){
        curr = curr.next ;
        res++;
    }
    return res ;
  }
}