【DP】 Record the longest increasing subsequence

In my last paper if it was called, I just work out  the length of the longest increasing subsequnce.But it's not enough to reach the goal.

In order to solve the problem by Dynamic Programming, I just modified the code I wrote last time.

Code as follows

#include <stdio.h>
int main()
{
  int num[] = {1, 3, 4, 5, 2, 6, 4, 9};
  int* L;
  int** pre; /*store the LIS*/
  int i, j;
  int longest = 0;
  int longest_index = 0;
  int k = 0;
  int num_len = sizeof(num) / sizeof(int);
  pre = (int**)malloc(num_len);
  for (i = 0; i < num_len; i++)
  {
    pre[i] = (int*)malloc(num_len);
  }
  system("cls");
  L = (int*)malloc(num_len);
  for (i = 0; i < num_len; i++)
  {
    L[i] = 1;
    for (j = 0; j < i; j++)
    {
      if (num[j] < num[i] && L[i] <= L[j] + 1)
      {
        L[i] = L[j] + 1;
        pre[i][k++] = num[j];
        if (L[i] > longest)
        {
          longest = L[i];
          longest_index = i;
        }
      }
    }
    pre[i][k] = num[i];
    k = 0;
  }
  for (i = 0; i <longest; i++)
  {
    printf("%d ", pre[longest_index][i]);
  }
  getchar();
  return 0;
}