#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct contour
{
    double start;
    double end;
    struct contour *next;
};
typedef struct contour Contour;
Contour *head;

void startList(double start_num, double end_num)
{
    if (head == NULL)
    {
        head = (Contour *)malloc(sizeof(Contour));
        head->start = start_num;
        head->end = end_num;
        head->next = NULL;
    }
}

void propagate(Contour *head)
{
    Contour *temp = head;

    if (temp != NULL)
    {
        Contour *newNode = (Contour *)malloc(sizeof(Contour));
        double diff = (((temp->end) - (temp->start)) / 3);

        newNode->end = temp->end;
        temp->end = ((temp->start) + diff);
        newNode->start = (newNode->end) - diff;

        newNode->next = temp->next;

        temp->next = newNode;

        propagate(temp->next->next);
    }
    else
        return;
}

void print(Contour *head)
{
    Contour *temp = head;
    while (temp != NULL)
    {
        printf("\t");
        printf("[%lf] -- ", temp->start);
        printf("[%lf]", temp->end);
        temp = temp->next;
    }

    printf("\n");
}

int main(int argc, char const *argv[])
{
    head = NULL;

    int start_num, end_num, levels;

    if (argc < 2)
    {
        printf("Enter 3 arguments: start_num \t end_num \t levels\n");
        scanf("%d %d %d", &start_num, &end_num, &levels);
    }
    else
    {
        start_num = atoi(argv[1]);
        end_num = atoi(argv[2]);
        levels = atoi(argv[3]);
    }

    startList(start_num, end_num);

    for (int i = 0; i < levels; i++)
    {
        printf("Level %d\t", i);
        print(head);
        propagate(head);
        printf("\n");
    }
    printf("Level %d\t", levels);
    print(head);

    return 0;
}