【劍指offer】Q15:鏈表中的倒數第K個結點

def FindKthToTail(head, k):
	if head == None: return None
	front = head; back = head
	steps = 0
	# get | front - head | = k
	while front and steps < k: 
		front = front.next
		steps += 1
	# less than k nodes 
	if front == None: return None

	while front:
		front = front.next
		back = back.next
	return back

與面試題37：兩個鏈表的第一個公共結點使用的是同樣的策略。