The penultimate K-node in the linked list

Problem Description:

Find the countdown k node in the list

Thinking Analysis:

With two pointers, one after the other, keep the k distance, the front pointer moves to the end, the back pointer is just right up to the K-node,

Consider the case where K is 0 and the penultimate K-node does not exist.

Reference code:

listnode* findkthtotail (ListNode * phead,unsigned int k)
{
if (NULL = = Phead | | k = = 0)
{
return NULL;
}

ListNode *pahead = Phead;

for (unsigned int i = 0;i < k-1;k++)
{
if (pahead->m_pnext! = NULL)
{
Pahead = pahead->m_pnext;
}
Else
{
return NULL;
}
}

ListNode *pbehind = Phead;
while (pahead->m_pnext! = NULL)
{
Pahead = pahead->m_pnext;
Pbehind = pbehind->m_pnext;
}

return pbehind;
}

K-nodes in the linked list