Cod sursă (job #388926)

#include <fstream>

using namespace std;

ifstream in("fotografie.in");
ofstream out("fotografie.out");

int n, m, p, q;

const int MOD = 666013;
const int base = 31;

int hashes[1001][1001];
int hashes2[1001][1001];

int put[1001];

char ch;

int main()
{
    in >> n >> m;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            in >> ch;
            hashes[i][j] = (hashes[i][j-1]*base+(ch-'a'))%MOD;
        }
    }
    put[0]=1;
    for(int i = 1; i <= n; i++)
        put[i] = (put[i-1]*base)%MOD;
    in >> p >> q;
    for(int i = 1; i <= p; i++)
    {
        for(int j = 1; j <= q; j++)
        {
            in >> ch;
            hashes2[i][j] = (hashes2[i][j-1]*base+(ch-'a'))%MOD;
        }
    }
    for(int i = 1; i <= n-p+1; i++)
    {
        for(int j = 1; j <= m-q+1; j++)
        {
            bool ok=true;
            for(int k = 1; k <= p && ok; k++)
            {
                if(((hashes[i+k-1][j+q-1]-hashes[i+k-1][j-1]*put[q])%MOD+MOD)%MOD != hashes2[k][q])
                    ok = false;
            }
            if(ok)
                out << i-1 << ' ' << j-1 << '\n';
        }
    }
    return 0;
}