LeetCode（剑指 Offer）- 22. 链表中倒数第k个节点

题目链接：点击打开链接

题目大意：略

解题思路：略

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AC 代码

• Java

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
// 解决方案(1)
class Solution {
    public ListNode getKthFromEnd(ListNode head, int k) {
        int len = 0;
        ListNode cur = head;
        while (cur != null) {
            len++;
            cur = cur.next;
        }
        k = len - k;
        for (int i = 0; i < k; i++) {
            head = head.next;
        }
        return head;
    }
}

// 解决方案(2)
class Solution {
    public ListNode getKthFromEnd(ListNode head, int k) {
        ListNode former = head, latter = head;
        for(int i = 0; i < k; i++)
            former = former.next;
        while(former != null) {
            former = former.next;
            latter = latter.next;
        }
        return latter;
    }
}

• C++

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* getKthFromEnd(ListNode* head, int k) {
        ListNode *former = head, *latter = head;
        for(int i = 0; i < k; i++)
            former = former->next;
        while(former != nullptr) {
            former = former->next;
            latter = latter->next;
        }
        return latter;
    }
};