题解 | #链表中倒数最后k个结点#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pHead ListNode类 
     * @param k int整型 
     * @return ListNode类
     */
     int func(ListNode *head){
        ListNode *cur =head;
        int sum = 0;
        while(cur != nullptr){
            cur = cur->next;
            sum++;
        }
        return sum;
     }
    ListNode* FindKthToTail(ListNode* pHead, int k) {
        // write code here
        ListNode * res = new ListNode(-1);
        res->next = pHead;
        ListNode *cur = res;
        int n = func(pHead);
        if(n == k){
            return res->next;
        }
        for(int i = 0; i<n-k;i++){
            cur = cur->next;
        }
        ListNode *temp = cur->next;
        res->next=temp;
        cur->next = nullptr;
        return res->next;
    }
};