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ortools-clone/examples/contrib/Partition.java
2018-11-07 20:49:03 +01:00

122 lines
4.2 KiB
Java

/**
* Copyright (c) 1999-2011, Ecole des Mines de Nantes
* All rights reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Ecole des Mines de Nantes nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import com.google.ortools.constraintsolver.*;
/**
* Partition n numbers into two groups, so that
* - the sum of the first group equals the sum of the second,
* - and the sum of the squares of the first group equals the sum of
* the squares of the second
* <br/>
*
* @author Charles Prud'homme
* @since 18/03/11
*/
public class Partition {
static {
System.loadLibrary("jniortools");
}
/**
* Partition Problem.
*/
private static void solve(int m) {
Solver solver = new Solver("Partition " + m);
IntVar[] x, y;
x = solver.makeIntVarArray(m, 1, 2 * m, "x");
y = solver.makeIntVarArray(m, 1, 2 * m, "y");
// break symmetries
for (int i = 0; i < m - 1; i++) {
solver.addConstraint(solver.makeLess(x[i], x[i + 1]));
solver.addConstraint(solver.makeLess(y[i], y[i + 1]));
}
solver.addConstraint(solver.makeLess(x[0], y[0]));
IntVar[] xy = new IntVar[2 * m];
for (int i = m - 1; i >= 0; i--) {
xy[i] = x[i];
xy[m + i] = y[i];
}
solver.addConstraint(solver.makeAllDifferent(xy));
int[] coeffs = new int[2 * m];
for (int i = m - 1; i >= 0; i--) {
coeffs[i] = 1;
coeffs[m + i] = -1;
}
solver.addConstraint(solver.makeScalProdEquality(xy, coeffs, 0));
IntVar[] sxy, sx, sy;
sxy = new IntVar[2 * m];
sx = new IntVar[m];
sy = new IntVar[m];
for (int i = m - 1; i >= 0; i--) {
sx[i] = solver.makeSquare(x[i]).var();
sxy[i] = sx[i];
sy[i] = solver.makeSquare(y[i]).var();
sxy[m + i] = sy[i];
}
solver.addConstraint(solver.makeScalProdEquality(sxy, coeffs, 0));
solver.addConstraint(
solver.makeSumEquality(x, 2 * m * (2 * m + 1) / 4));
solver.addConstraint(
solver.makeSumEquality(y, 2 * m * (2 * m + 1) / 4));
solver.addConstraint(
solver.makeSumEquality(sx, 2 * m * (2 * m + 1) * (4 * m + 1) / 12));
solver.addConstraint(
solver.makeSumEquality(sy, 2 * m * (2 * m + 1) * (4 * m + 1) / 12));
DecisionBuilder db = solver.makeDefaultPhase(xy);
SolutionCollector collector = solver.makeFirstSolutionCollector();
collector.add(xy);
SearchMonitor log = solver.makeSearchLog(10000);
solver.newSearch(db, log, collector);
solver.nextSolution();
System.out.println("Solution solution");
for (int i = 0; i < m; ++i) {
System.out.print("[" + collector.value(0, xy[i]) + "] ");
}
System.out.printf("\n");
for (int i = 0; i < m; ++i) {
System.out.print("[" + collector.value(0, xy[m+i]) + "] ");
}
System.out.println();
}
public static void main(String[] args) throws Exception {
Partition.solve(32);
}
}