Flattening a Linked List

Problem Description:

Given a Linked List where every node represents a linked list and contains two pointers of its type:
(i) a next pointer to the next node
(ii) abottompointerto a linked list where this node is head.
You have to flatten the linked list to a single linked list which is sorted. For Ex: Shown below is a given linked list

5 -> 10 -> 19 -> 28
       |    |     |     |
       V    V     V     V
       7    20    22    35
       |          |     |
       V          V     V
       8          50    40
       |                |
       V                V
       30               45

and after flattening it, the sorted linked listlooks like: 5->7->8->10->19->20->22->28->30->35->40->45->50
The node structure has3fields as mentioned. Anext pointer, abottompointerand a data part.
There are multiple test cases. For each test case, this functionwill be called individually.
Note :All linked listsare sorted.

Problem Link

/* node structure  used in the program
struct node{
	int data;
	struct node * next;
	struct node * bottom ;
}; */

/*  Function which returns the  root of
    the flattened linked list. */

node *flatten(node *root)
{
   // Your code here
  int mn,lastIdx;
  bool first=0;
  node *nodes[55];
  node *nNode,*nRoot;
  node *tmp;
  int idx=0;
  nodes[idx]=root;
  tmp=root->next;
  while(tmp)
  {
      idx=idx+1;
      nodes[idx]=tmp;
      tmp=tmp->next;
  }

  while(1)
  {
      mn=100000;
      lastIdx=-1;
        for(int i=0;i<=idx;i++)
        {
              if(nodes[i]!=NULL)
              {
                  if(mn>nodes[i]->data)
                  {
                      lastIdx=i;
                      mn=nodes[i]->data;
                  }
              }
        }
        if(lastIdx==-1)
        break;
        if(first==0)
        {
            nNode=nodes[lastIdx];
            nRoot=nNode;
            first=1;
        }
        else
        {
            nNode->bottom=nodes[lastIdx];
            nNode=nNode->bottom;
        }
        nodes[lastIdx]=nodes[lastIdx]->bottom;
  }
   return nRoot;
}