https://pintia.cn/problem-sets/994805342720868352/problems/994805394512134144

老师,我想问下
for (int i = 0; i < (sum/k*k); i++)//处理尾巴前的节点
result[i] = list[i / k * k + k - 1 - i % k];
这里的list[]里面这个索引写法,怎么解释得到的?

#include
#include
using namespace std;
int main()
{
int first, k, n, sum = 0;
cin >> first >> n >> k;
int temp, data[100005], next[100005], list[100005], result[100005];
for (int i = 0; i < n; i++)
{
cin >> temp;
cin >> data[temp] >> next[temp];
}
while (first != -1)
{
list[sum++] = first;
first = next[first];
}
for (int i = 0; i < sum; i++)
result[i] = list[i];
//
for (int i = 0; i < (sum/k*k); i++)//处理尾巴前的节点
result[i] = list[i / k * k + k - 1 - i % k];
for (int i = 0; i < sum - 1; i++) //打印数据,对于最后的数据额外处理
printf("%05d %d %05d\n", result[i], data[result[i]], result[i + 1]);
printf("%05d %d -1", result[sum - 1], data[result[sum - 1]]);
return 0;
}