Linked list splits into small linked list, every two of them length difference at most 1.

SplitSmallLinkedList_iterative.cs

List<ListNode> SplitToMutipleLinkedListGivenValue(ListNode root, int number)
{
    if(root == null || number < 1)
    {
        return new ArrayList();
    }
    
    // base case 
    if( number == 1)
        return root;
        
    int length = getLength(root);
    int smallListLength = length / number; 
    int reside = length % number;
    
    List<ListNode> smallLists = new List<ListNode>(); 
    
    int index = 0; 
    Node rootNode = root; 
    Node current = root; 
    Node previous = null; 
       
    while(index < number)
    {
      // index == 0 first list 
      int currentLength = (index < residue)? (smallListLength + 1) : smallListLength ; 
      
      // go over the current list
      List current = null, previous = null;
       
       int indexSmall = 0 ; 
       while(indexSmall < currentLength )  // 0 < 2
       {
          previous = current;//2
          current = current.Next; //3
          indexSmall ++; //2
       }
       
       // add the output 
       previous.Next = null; 
       smallList.Add(rootNode); 
       
       // 
       rootNode = current; 
       previous = null; 
      
      index ++;   
    }          
    
    return smallLists ; 
}