#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

void usage(char * prog);
void similarityMatrix(vector<char> & s, vector<char> & t);
bool readFile(char * fileName, vector<char> & v);

void usage(char * prog)
{
    cout << "Usage: " << prog << " <file1> <file2>" << endl;
    exit(42);
}

int main(int argc, char * argv[])
{
    vector<char> file1, file2;

    if (argc < 3)
        usage(argv[0]);

    readFile(argv[1], file1);
    readFile(argv[2], file2);

    similarityMatrix(file1, file2);
}

bool readFile(char * fileName, vector<char> & v)
{
    ifstream in(fileName);
    if (!in.is_open())
        return false;
    while (!in.eof())
    {
        char chr;
        in >> chr;
        v.push_back(chr);
    }
    return true;
}

void similarityMatrix(vector<char> & s, vector<char> & t)
{
    int s_size = s.size();
    int t_size = t.size();
    int F[s_size][t_size];
    for (int i = 0; i < t_size; i++)
        F[0][i] = 0;
    for (int i = 0; i < s_size; i++)
        F[i][0] = 0;
    for (int i = 1; i < s_size; i++)
    {
        for (int j = 1; j < t_size; j++)
        {
            F[i][j] =
                max(
                    max(
                        F[i][j-1] - 2,
                        F[i-1][j-1] + (s[i] == t[j] ? 1 : -1)
                    ),
                    max(
                        F[i-1][j] - 2,
                        0
                    )
                );
        }
    }
#if 0
    cout << "Matrix: " << s_size << " x " << t_size << endl;
    for (int i = 0; i < s_size; i++)
    {
        for (int j = 0; j < t_size; j++)
        {
            printf("%02d ", F[i][j]);
        }
        printf("\n");
    }
#endif
}