Imperii

#include <fstream>

using namespace std;

FILE *fin, *fout;

int n, m, ic, sc, M[1010][1010], M1[1010][1010], M2[1010][1010], M3[1010][1010], M4[1010][1010], p, q, r;
int dl[4] = {-1, 0, 1, 0}, dc[4] = {0, 1, 0, -1};
char c, c1, c2, c3, c4;

struct coada
{
    int l, c;
};
coada C[1000010], acum, urm;

void citire();
void bordare(int A[1010][1010]);
void lee(int x, int y, int A[1010][1010]);
int comparare(int a, int b, int c, int d);

int main()
{
    fin = fopen("imperii.in", "r");
    fout = fopen("imperii.out", "w");
    citire();
    bordare(M1);
    bordare(M2);
    bordare(M3);
    bordare(M4);
    lee(1, 1, M1);
    lee(1, m, M2);
    lee(n, 1, M3);
    lee(n, m, M4);
    for (p = 1; p <= n; p++)
    {
        for (q = 1; q <= m; q++)
        {
            if (M[p][q] == -1)
            {
                fprintf(fout, "#");
                continue;
            }
            r = comparare(M1[p][q], M2[p][q], M3[p][q], M4[p][q]);
            if (r == 1)
                fprintf(fout, "%c", c1);
            else if (r == 2)
                fprintf(fout, "%c", c2);
            else if (r == 3)
                fprintf(fout, "%c", c3);
            else if (r == 4)
                fprintf(fout, "%c", c4);
            else
                fprintf(fout, "-");
        }
        fprintf(fout, "\n");
    }
    return 0;
}
void citire()
{
    int i, j;
    fscanf(fin, "%d%d\n", &n, &m);
    for (i = 1; i <= n; i++)
    {
        for (j = 1; j <= m; j++)
        {
            fscanf(fin, "%c", &c);
            if (c == '#')
                M[i][j] = -1;
            if (i == 1 && j == 1)
                c1 = c;
            else if (i == 1 && j == m)
                c2 = c;
            else if (i == n && j == 1)
                c3 = c;
            else if (i == n && j == m)
                c4 = c;
        }
        fscanf(fin, "\n");
    }
}
void bordare(int A[1010][1010])
{
    int i, j;
    for (i = 0; i <= n + 1; i++)
        A[i][0] = A[i][m + 1] = -1;
    for (j = 0; j <= m + 1; j++)
        A[0][j] = A[n + 1][j] = -1;
}
void lee(int x, int y, int A[1010][1010])
{
    int k;
    ic = 0;
    sc = -1;
    C[++sc].l = x;
    C[sc].c = y;
    A[x][y] = 1;
    while (ic <= sc)
    {
        acum = C[ic++];
        for (k = 0; k < 4; k++)
        {
            urm.l = acum.l + dl[k];
            urm.c = acum.c + dc[k];
            if (!M[urm.l][urm.c] && !A[urm.l][urm.c])
            {
                A[urm.l][urm.c] = A[acum.l][acum.c] + 1;
                C[++sc] = urm;
            }
        }
    }
}
int comparare(int a, int b, int c, int d)
{
    if (a < b && a < c && a < d && a > 0)
        return 1;
    if (b < a && b < c && b < d && b > 0)
        return 2;
    if (c < a && c < b && c < d && c > 0)
        return 3;
    if (d < a && d < b && d < c && d > 0)
        return 4;
    return 0;
}