private static void test01()
//****************************************************************************80
//
// Purpose:
//
// TEST01 seeks a selection of binary powers that have a given sum.
//
// Discussion:
//
// We consider the binary powers 1, 2, 4, ... 2^(n-1).
//
// We wish to select some of these powers, so that the sum is equal
// to a given target value. We are actually simply seeking the binary
// representation of an integer.
//
// A partial solution is acceptable if it is less than the target value.
//
// We list the powers in descending order, so that the bactracking
// procedure makes the most significant choices first, thus quickly
// eliminating many unsuitable choices.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 01 January 2014
//
// Author:
//
// John Burkardt
//
{
int[] choice = new int[8];
const int n = 8;
bool reject = false;
int[] targets =
{
73, 299, -3
}
;
int test;
const int test_num = 3;
Console.WriteLine("");
Console.WriteLine("TEST01");
Console.WriteLine(" Use BACKBIN_RC to find the binary expansion of");
Console.WriteLine(" an integer between 0 and 255.");
Console.WriteLine(" The choices are 0/1 for the 8 digits.");
for (test = 0; test < test_num; test++)
{
int target = targets[test];
Console.WriteLine("");
Console.WriteLine(" TARGET = " + target + "");
int call_num = 0;
int n2 = -1;
int i;
for (;;)
{
BacktrackBinary.backbin_rc(n, reject, ref n2, ref choice);
call_num += 1;
if (n2 == -1)
{
Console.WriteLine(" Termination without solution.");
break;
}
//
// Evaluate the integer determined by the choices.
//
int factor = 1;
for (i = n; n2 < i; i--)
{
factor *= 2;
}
int result = 0;
for (i = 0; i < n2; i++)
{
result = result * 2 + choice[i];
}
result *= factor;
//
// If the integer is too big, then we reject it, and
// all the related integers formed by making additional choices.
//
reject = target < result;
//
// If we hit the target, then in this case, we can exit because
// the solution is unique.
//
if (result == target)
{
break;
}
}
Console.WriteLine(" Number of calls = " + call_num + "");
Console.WriteLine(" Binary search space = " + Math.Pow(2, n) + "");
string cout = " ";
for (i = 0; i < n; i++)
{
cout += choice[i].ToString().PadLeft(2);
}
Console.WriteLine(cout);
}
}
private static void test02()
//****************************************************************************80
//
// Purpose:
//
// TEST02 seeks a subset of a set of numbers which add to a given sum.
//
// Licensing:
//
// This code is distributed under the GNU LGPL license.
//
// Modified:
//
// 01 January 2014
//
// Author:
//
// John Burkardt
//
{
int[] choice = new int[8];
const int n = 8;
bool reject = false;
const int target = 53;
int[] w =
{
15, 22, 14, 26, 32, 9, 16, 8
}
;
Console.WriteLine("");
Console.WriteLine("TEST02");
Console.WriteLine(" Use BACKBIN_RC to seek subsets of a set W");
Console.WriteLine(" that sum to a given target value.");
Console.WriteLine(" The choices are 0/1 to select each element of W.");
Console.WriteLine("");
Console.WriteLine(" TARGET = " + target + "");
Console.WriteLine("");
int call_num = 0;
int n2 = -1;
for (;;)
{
BacktrackBinary.backbin_rc(n, reject, ref n2, ref choice);
call_num += 1;
if (n2 == -1)
{
break;
}
//
// Evaluate the partial sum.
//
int result = 0;
int i;
for (i = 0; i < n2; i++)
{
result += choice[i] * w[i];
}
//
// If the sum is too big, then we reject it, and
// all the related sums formed by making additional choices.
//
reject = target < result;
//
// If we hit the target, print out the information.
//
if (result == target && n2 == n)
{
string cout = " ";
for (i = 0; i < n; i++)
{
cout += choice[i].ToString().PadLeft(2);
}
Console.WriteLine(cout);
}
}
Console.WriteLine("");
Console.WriteLine(" Number of calls = " + call_num + "");
Console.WriteLine(" Binary search space = " + Math.Pow(2, n) + "");
}
