/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 * Main authors:
 * Christian Schulte <schulte@gecode.org>
 *
 * Copyright:
 * Christian Schulte, 2003
 *
 * This file is part of Gecode, the generic constraint
 * development environment:
 * http://www.gecode.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <gecode/driver.hh>
#include <gecode/int.hh>
#include <gecode/minimodel.hh>

using namespace Gecode;

/**
 * \brief %Example: partition numbers into two groups
 *
 * \ingroup Example
 */
class Partition : public Script {
protected:
 /// First group of numbers
 IntVarArray x;
 /// Second group of numbers
 IntVarArray y;
public:
 /// Actual model
 Partition(const SizeOptions& opt)
 : Script(opt),
 x(*this,opt.size(),1,2*opt.size()),
 y(*this,opt.size(),1,2*opt.size()) {
 const int n = opt.size();

 // Break symmetries by ordering numbers in each group
 rel(*this, x, IRT_LE);
 rel(*this, y, IRT_LE);

 rel(*this, x[0], IRT_LE, y[0]);

 IntVarArgs xy(2*n);
 for (int i = n; i--; ) {
 xy[i] = x[i]; xy[n+i] = y[i];
 }
 distinct(*this, xy, opt.ipl());

 IntArgs c(2*n);
 for (int i = n; i--; ) {
 c[i] = 1; c[n+i] = -1;
 }
 linear(*this, c, xy, IRT_EQ, 0);

 // Array of products
 IntVarArgs sxy(2*n), sx(n), sy(n);

 for (int i = n; i--; ) {
 sx[i] = sxy[i] = expr(*this, sqr(x[i]));
 sy[i] = sxy[n+i] = expr(*this, sqr(y[i]));
 }
 linear(*this, c, sxy, IRT_EQ, 0);

 // Redundant constraints
 linear(*this, x, IRT_EQ, 2*n*(2*n+1)/4);
 linear(*this, y, IRT_EQ, 2*n*(2*n+1)/4);
 linear(*this, sx, IRT_EQ, 2*n*(2*n+1)*(4*n+1)/12);
 linear(*this, sy, IRT_EQ, 2*n*(2*n+1)*(4*n+1)/12);

 branch(*this, xy, INT_VAR_AFC_SIZE_MAX(opt.decay()), INT_VAL_MIN());
 }

 /// Constructor used during cloning \a s
 Partition(Partition& s) : Script(s) {
 x.update(*this, s.x);
 y.update(*this, s.y);
 }
 /// Copying during cloning
 virtual Space*
 copy(void) {
 return new Partition(*this);
 }
 /// Print solution
 virtual void
 print(std::ostream& os) const {
 os << "\t";
 int a, b;
 a = b = 0;
 for (int i = 0; i < x.size(); i++) {
 a += x[i].val();
 b += x[i].val()*x[i].val();
 os << x[i] << ", ";
 }
 os << " = " << a << ", " << b << std::endl << "\t";
 a = b = 0;
 for (int i = 0; i < y.size(); i++) {
 a += y[i].val();
 b += y[i].val()*y[i].val();
 os << y[i] << ", ";
 }
 os << " = " << a << ", " << b << std::endl;
 }
};

/**
 * \brief Main-functiona
 * \relates Partition
 */
int
main(int argc, char* argv[]) {
 SizeOptions opt("Partition");
 opt.size(32);
 opt.ipl(IPL_BND);
 opt.parse(argc,argv);
 Script::run<Partition,DFS,SizeOptions>(opt);
 return 0;
}


// STATISTICS: example-any