剑指offer 链表中倒数第k个节点

#include<iostream>

using namespace std;

struct ListNode
{
	int m_nValue;
	ListNode* m_pNext;
};


ListNode* FindKthToTail(ListNode* pListHead, unsigned int k)
{
	//注意代码鲁棒性
	if (pListHead == nullptr || k == 0)
		return nullptr;
	ListNode* pAhead = pListHead;
	ListNode* pBehind = nullptr;

	for (unsigned int i = 0; i < k - 1; ++i)
	{
		if (pAhead->m_pNext != nullptr)
			pAhead = pAhead->m_pNext;
		else
		{
			return nullptr;
		}
	}
	pBehind = pListHead;
	while (pAhead->m_pNext != nullptr)
	{
		pAhead = pAhead->m_pNext;
		pBehind = pBehind->m_pNext;
	}
	return pBehind;


}


int main()
{
	ListNode* head = new ListNode();
	head->m_nValue = 1;
	head->m_pNext = nullptr;

	ListNode* a = new ListNode();
	a->m_nValue = 2;
	a->m_pNext = nullptr;
	head->m_pNext = a;

	ListNode* b = new ListNode();
	b->m_nValue = 3;
	b->m_pNext = nullptr;
	a->m_pNext = b;

	ListNode* c = new ListNode();
	c->m_nValue = 4;
	c->m_pNext = nullptr;
	b->m_pNext = c;

	ListNode* d = new ListNode();
	d->m_nValue = 5;
	d->m_pNext = nullptr;
	c->m_pNext = d;

	ListNode* e = new ListNode();
	e->m_nValue = 6;
	e->m_pNext = nullptr;
	d->m_pNext = e;

	ListNode* find = new ListNode();

	find = FindKthToTail(head, 3);

	cout << find->m_nValue << endl;
	cin.get();
	return 0;
}