題目描述

輸入一個連結串列，輸出該連結串列中倒數第k個結點

題目連結：https://www.nowcoder.com/practice/529d3ae5a407492994ad2a246518148a

public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        if (head == null) return head;
        ListNode first = head;
        ListNode sec = head;
        for
 
 (int i = 0; i < k; i++) {
            sec = sec.next;
            if (sec == null && i != (k-1)) return null;
        }
        // 要的是正數第一個
        if (sec == null) return head;
        // 否則
        while (sec != null) {
            first = first.next;
            sec = sec.next;
        }
        return
 
 first;
    }
}