pastebin.run

procedure euclid_gcd (integer val a, integer val n, integer gcd, integer inverse)
{
    call euclid_rec(a, n, 1, 0, 0, 1, gcd, inverse);
    inverse <- mod(inverse, n);
}

procedure euclid_rec (integer val r', integer val r, integer val s', integer val s,
                      integer val t', integer val t, integer gcd, integer inverse)
    integer temp;
    integer quotient;
    procedure (integer val q, integer prev, integer curr) -> void euclid_step;
{
    if r = 0 then
        gcd <- r;
        inverse <- s';
    else
        euclid_step <- lambda (integer val quotient, integer prev, integer curr)
            integer temp;
        {
            temp <- prev;
            prev <- curr;
            curr <- temp - quotient * curr;
        };

quotient <- r' / r;
        call euclid_step(quotient, r', r);
        call euclid_step(quotient, s', s);
        call euclid_step(quotient, t', t);
        call euclid_rec(r', r, s', s, t', t, gcd, inverse);
    fi
}

procedure main ()
	integer gcd;
    integer inverse;
{
    call euclid_gcd(37551, 17, gcd, inverse);
    writeln inverse;
}