剑指Offer - 面试题22. 链表中倒数第k个节点（快慢指针）

示例：
给定一个链表: 1->2->3->4->5, 和 k = 2.
返回链表 4->5.

class Solution {
public:
    ListNode* getKthFromEnd(ListNode* head, int k) {
        ListNode *fast = head, *slow = head;
        while(k--)
        	fast = fast->next;
        while(fast)
        {
        	fast = fast->next;
        	slow = slow->next;
        }
        return slow;
    }
};

class Solution {
public:
    int kthToLast(ListNode* head, int k) {
    	ListNode *fast = head, *slow = head;
    	while(k--)
    		fast = fast->next;
    	while(fast)
    	{
    		fast = fast->next;
    		slow = slow->next;
    	}
    	return slow->val;
    }
};