#include <ios>
#include <vector>
#include <iostream>
#include <iomanip>
using namespace std;
#define TYPE int
#define line vector<TYPE>
#define matrix vector<line>
#define DEBUG(args) // cout << args << endl
#define DEBUG2(args)  cout << args << endl

class diagonMatrix{
  public:
    diagonMatrix( int dim );
    diagonMatrix( matrix );
    int index( int i, int j );
    void edit( int i, int j, TYPE value );
    void print();
    matrix data;
};

int main(){
  matrix razr = { {1, 0, 0, 0, 0, 0, 0},
                  {0, 2, 8, 9, 0, 0, 0},
                  {0, 8, 3, 0, 0, 0, 0},
                  {0, 9, 0, 4, 10,0, 0},
                  {0, 0, 0, 10,5, 11,12},
                  {0, 0, 0, 0, 11,6, 0},
                  {0, 0, 0, 0, 12,0, 7} };

/*
  matrix razr = { {1,2,3},
                  {4,5,6},
                  {7,8,9} };
*/

  int len = razr.size();

  diagonMatrix M1( razr );


  diagonMatrix M2( razr );

  diagonMatrix M3( razr.size() );

  for( int i = 0; i < len; i++ ){
    for( int j = 0; j < len; j++ ){
      M3.edit(i, j, 0);
      for( int k = 0; k < len; k++ ){
        int E1 = M1.index(i, k);
        int E2 = M2.index(k, j);
        int E3 = M3.index(i, j);
        M3.edit(i, j, E1*E2+E3);
      }
    }
  }


  M3.print();

}


diagonMatrix::diagonMatrix( int dim ){
  for( int i = 0; i < dim; i++ ){
    data.push_back(line());
  }
}

diagonMatrix::diagonMatrix( matrix m ){
  int len = m.size();

  line tmp;
  for( int i = 0; i  < len; i++ ){
    tmp.push_back(0);
  }
  for( int i = 0; i  < len; i++ ){
    data.push_back(tmp);
  }



  for( int i = 0; i < len; i++ ){
    for( int j = 0; j < len; j++ ){
      int I = 1-len + i + j;
      int J = j;
      int elem = 0;
      if( I >= 0 ){
        elem = m[I][J];
      }
      data[j][i] = elem;
    }
  }

  matrix data_copy = data;
  for( int i = 0; i < len; i++ ){
    bool empty_row = true;
    for( int j = 0; j < len; j++ ){
      if( data[j][i] != 0 ){
        empty_row = false;
      }
    }
    if( !empty_row ){
      break;
    }else{
      for( int j = 0; j < len; j++ ){
        data_copy[j].erase( data_copy[j].begin() ) ;
      }
    }
  }
  data = data_copy;

  /**/

  for( int i = 0; i < data.size(); i++ ){
    for( int j = 0; j < data[i].size(); j++ ){
      cout << data[i][j] << ' ';
    } cout << endl;
  }

}

void diagonMatrix::print(){
  int len = data.size();
  for( int i = 0; i < len; i++ ){
    for( int j = 0; j < len; j++ ){
      cout << right << setw(4) << diagonMatrix::index(i, j) << ' ';
    }
    cout << endl;
  }
}


int diagonMatrix::index( int i, int j ){

  int len = data.size();
  int depth = data[0].size();

  if( i < j ){
    int tmp = i;
    i = j;
    j = tmp;
  }

  int di = i - j;
  int I = i;
  int J = depth - di - 1;

  int elem = 0;
  if( J >= 0 )
    elem = data[I][J];
  return elem;

}

void diagonMatrix::edit( int i, int j, int val ){

  int len = data.size();
  int depth = data[0].size();

  if( i < j ){
    int tmp = i;
    i = j;
    j = tmp;
  }

  int di = i - j;
  int I = i;
  int J = depth - di - 1;


  while( J < 0 ){
    for( int i = 0; i < data.size(); i++ )
      data[i].insert( data[i].begin(), 0 );
    J++;
  }

  data[I][J] = val;


  return;

}