intervale greedy nu stiu sigur

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

struct interval
{
    int low, high;
};

void citire(FILE *fin, int *n, int *a, int *b, struct interval *ptr)
{
    fscanf(fin,"%d",&(*a));
    fscanf(fin,"%d",&(*b));
    fscanf(fin,"%d",&(*n));

    int i;

    for (i=0; i<*n; i++)
    {
        fscanf(fin,"%d %d",&ptr->low,&ptr->high);
        ptr++;
    }

}

void afisare(FILE *fout, int n, int a, int b, struct interval *ptr)
{
    fprintf(fout,"Vector sortat crescator dupa high:\n");

    int i;

    fprintf(fout,"Intervalul [%d,%d]\n",a,b);

    fprintf(fout,"%d\n",n);

    for (i=0; i<n; i++)
    {
        fprintf(fout,"%d %d \n", ptr->low, ptr->high);
        ptr++;
    }

}

int comparator(const void *s1, const void *s2) //asta e pentru quicksort
{
    struct interval *e1 = (struct interval *) s1;
    struct interval *e2 = (struct interval *) s2;

    return e1->high - e2->high;
}

void greedy(FILE *fout, int n, int a, int b, struct interval *v)
{
    fprintf(fout,"\n********************************************************\nRezolvare:\n");

    int i=0, low_aux, high_aux;

    while (a <= b)
    {
        while (v[i].low <= a && v[i].high > a && i<n)
        {
            low_aux = v[i].low;
            high_aux = v[i].high;
            i++;
        }
        a = high_aux;
        fprintf(fout,"%d %d\n",low_aux,high_aux);
    }

}

int main()
{
    FILE *fin, *fout;

    fin = fopen("date.in","r");
    fout = fopen("date.out","w");

    struct interval vec[100];
    int n,a,b;

    citire(fin,&n,&a,&b,vec);
    qsort(vec,n,sizeof(struct interval),comparator);
    afisare(fout,n,a,b,vec);
    greedy(fout,n,a,b,vec);

    return 0;
}

//cod luat
#include <stdio.h>
#include <stdlib.h>
struct Interval
{
    int a,b;
};
int cmp (const void *p, const void *q)
{
    struct Interval vp = *(struct Interval *)p;
    struct Interval vq = *(struct Interval *)q;
    return vp.b - vq.b;
}

int main()
{
    int n , i, A, B, aaux, baux;
    printf("n="); scanf("%d", &n);
    printf("A="); scanf("%d", &A);
    printf("B="); scanf("%d", &B);
    printf("Intervalele: ");
    struct Interval v[100];
    for(i = 0; i < n; i++)
        scanf("%d%d", &v[i].a, &v[i].b);
    qsort (v, n, sizeof(struct Interval), cmp);
    i=0;
    while (A <=B)
    {
        while (v[i].a <= A && v[i].b > A && i<n)
            {
                aaux = v[i].a;
                baux = v[i].b;
                i++;
            }
        A=baux;
        printf("[%d,%d]\n", aaux, baux);
    }

    return 0;
}