技巧：创建一个空的头指针，方便翻转后的连接原链表的操作

C++ 代码

#include <iostream>
#include <algorithm>
using namespace std;

const int MAX_N = 100010;

int ne[MAX_N];
int node[MAX_N];

int Reverse(int head, int k) {
    int rear = ne[head]; //反转后的最后一个结点
    int pL = ne[head]; //从头结点的下个结点开始翻转
    int pR = ne[pL];
    for (int i = 0; i < k - 1; i++) { //k个节点翻转k-1次
        int t = ne[pR];
        ne[pR] = pL;
        pL = pR;
        pR = t;
    }
    //将反转后的链表与未反转链表连起来
    ne[head] = pL;
    ne[rear] = pR;
    return rear; //返回翻转链表的最后一个节点
}

int main() {
    int head, p;
    int h, n, k;
    cin >> h >> n >> k;

    //创建空的头指针
    head = MAX_N - 1;
    ne[head] = h;

    for (int i = 0; i < n; i++) {
        int addr, data, nextAddr;
        cin >> addr >> data >> nextAddr;
        node[addr] = data;
        ne[addr] = nextAddr;
    }
    //统计有效链表的长度
    p = head;
    int cnt = 0;
    while (p != -1) {
        p = ne[p];
        cnt++;
    }
    n = cnt;

    //翻转链表
    p = head;
    for (int i = 0; i + k < n; i += k) p = Reverse(p, k);

    //打印链表
    p = ne[head];
    while (p != -1) {
        printf("%05d %d ", p, node[p]);
        if (ne[p] != -1) printf("%05d\n", ne[p]);
        else puts("-1");
        p = ne[p];
    }
    return 0;
}