// Laboratorio 2 - Esercizio 2
// Matteo Schiff - s295565

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

int ** matrmalloc(int * nc, int * nr) {
    FILE *fp_read;

    if ((fp_read = fopen("mat.txt", "r")) == NULL)
    {
        puts("Impossibile aprire il file");
        return NULL;
    }

    fscanf(fp_read, "%u %u\n", nr, nc);

    int ** mat = malloc(*nr * sizeof(int *));

    for (int i = 0; i < *nr; i++) {
        int * row = malloc(*nc * sizeof(int));
        for (int j = 0; j < *nc; j++) {
            fscanf(fp_read, "%d ", &row[j]);
        }
        mat[i] = row;
    }

    fclose(fp_read);
    return mat;
}

void matrfree(int **mat, int nr) {
    for (int i = 0; i < nr; i++) {
        free(mat[i]);
    }

    free(mat);
}

void separa(int **mat, int nr, int nc, int ** bianchi, int ** neri, int * nbianchi, int * nneri) {
    int a = nc % 2;
    int x = nc / 2;
    int b = nr % 2;
    int y = nr / 2;

    *nneri = (x + a) * y + x * (y + b);
    *nbianchi = x * y + (x+a) * (y + b);

    *bianchi = malloc(*nbianchi * sizeof(int));
    *neri = malloc(*nneri * sizeof(int));

    int conta_bianchi = 0, conta_neri = 0;

    for (int i = 0; i < nr; i++) {
        for (int j = 0; j < nc; j++) {
            if ((i+j) % 2 == 0) {
                (*bianchi)[conta_bianchi++] = mat[i][j];
            } else {
                (*neri)[conta_neri++] = mat[i][j];
            }
        }
    }
}

int main(int argc, char ** argv) {
    int nc, nr;
    int ** mat = matrmalloc(&nc, &nr);

    if (mat == NULL) {
        return 1;
    }

    int *bianchi, *neri, n_bianchi, n_neri;
    separa(mat, nr, nc, &bianchi, &neri, &n_bianchi, &n_neri);

    puts("Numeri su caselle bianche:");
    for (int i = 0; i < n_bianchi; i++)
        printf("%u\n", bianchi[i]);

    puts("Numeri su caselle nere:");
    for (int i = 0; i < n_neri; i++)
        printf("%u\n", neri[i]);

    matrfree(mat, nr);
    free(bianchi);
    free(neri);

    return 0;
}