222 lines
7.0 KiB
Java
222 lines
7.0 KiB
Java
// Copyright 2011 Hakan Kjellerstrand hakank@bonetmail.com
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package com.google.ortools.constraintsolver.samples;
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import java.io.*;
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import java.util.*;
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import java.text.*;
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import com.google.ortools.constraintsolver.DecisionBuilder;
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import com.google.ortools.constraintsolver.IntVar;
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import com.google.ortools.constraintsolver.Solver;
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import com.google.ortools.constraintsolver.*;
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import com.google.ortools.constraintsolver.Solver.*;
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public class SendMoreMoney2 {
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static Solver sol;
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static {
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System.loadLibrary("jniconstraintsolver");
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}
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//
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// Some helper methods
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//
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static IntExpr p(IntExpr a, int b, IntExpr c) {
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return sol.makeSum(sol.makeProd(a, b), c);
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}
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static IntExpr p(IntVar a, int b) {
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return sol.makeProd(a, b);
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}
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// a slighly more intelligent scalar product
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static IntExpr sp(IntVar[] a) {
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int len = a.length;
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int c = 1;
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int[] t = new int[len];
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for(int i = len-1; i >= 0; i--) {
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t[i] = c;
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c *= 10;
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}
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return sol.makeScalProd(a, t);
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}
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/**
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*
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* Solves the SEND+MORE=MONEY problem with different approaches.
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*
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*/
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private static void solve(int alt) {
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sol = new Solver("SendMoreMoney");
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int base = 10;
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//
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// variables
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//
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IntVar s = sol.makeIntVar(0, base-1, "s");
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IntVar e = sol.makeIntVar(0, base-1, "e");
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IntVar n = sol.makeIntVar(0, base-1, "n");
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IntVar d = sol.makeIntVar(0, base-1, "d");
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IntVar m = sol.makeIntVar(0, base-1, "m");
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IntVar o = sol.makeIntVar(0, base-1, "o");
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IntVar r = sol.makeIntVar(0, base-1, "r");
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IntVar y = sol.makeIntVar(0, base-1, "y");
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IntVar[] x = {s,e,n,d,m,o,r,y};
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//
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// Constraints
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//
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/*
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*
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* Below are some alternatives encodings of the
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* same idea:
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*
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* 1000*s + 100*e + 10*n + d +
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* 1000*m + 100*o + 10*r + e ==
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* 10000*m + 1000*o + 100*n + 10*e + y
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*
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*/
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if (alt == 0) {
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//
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// First, a version approach which is just too noisy.
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//
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sol.addConstraint(
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sol.makeEquality(
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sol.makeSum(sol.makeSum(
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sol.makeProd(s,1000),
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sol.makeSum(sol.makeProd(e,100),
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sol.makeSum(sol.makeProd(n,10),
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sol.makeProd(d,1)))),
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sol.makeSum(
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sol.makeProd(m,1000),
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sol.makeSum(sol.makeProd(o,100),
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sol.makeSum(sol.makeProd(r,10),
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sol.makeProd(e,1))))
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).Var(),
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sol.makeSum(sol.makeProd(m,10000),
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sol.makeSum(
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sol.makeProd(o,1000),
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sol.makeSum(
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sol.makeProd(n,100),
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sol.makeSum(
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sol.makeProd(e,10),
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sol.makeProd(y,1))))).Var()));
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} else if (alt == 1) {
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//
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// Alternative 1, using the helper methods
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//
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// p(IntExpr, int, IntExpr) and
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// p(IntVar, int)
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//
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sol.addConstraint(
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sol.makeEquality(
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sol.makeSum(p(s,1000,p(e,100,p(n,10,p(d,1)))),
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p(m,1000,p(o,100,p(r,10,p(e,1))))).Var(),
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p(m,10000,p(o,1000,p(n,100,p(e,10,p(y,1))))).Var()));
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} else if (alt == 2) {
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//
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// Alternative 2
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//
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sol.addConstraint(
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sol.makeEquality(
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sol.makeSum(
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sol.makeScalProd(new IntVar[] {s,e,n,d},
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new int[] {1000,100,10,1}),
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sol.makeScalProd(new IntVar[] {m,o,r,e},
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new int[] {1000,100,10,1})).Var(),
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sol.makeScalProd(new IntVar[] {m,o,n,e,y},
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new int[] {10000,1000,100,10,1}).Var()));
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} else if (alt == 3) {
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//
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// alternative 3: same approach as 2, with some helper methods
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//
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sol.addConstraint(
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sol.makeEquality(sol.makeSum(sp(new IntVar[] {s,e,n,d}),
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sp(new IntVar[] {m,o,r,e})).Var(),
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sp(new IntVar[] {m,o,n,e,y}).Var()));
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} else if (alt == 4) {
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//
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// Alternative 4, using explicit variables
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//
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IntExpr send = sol.makeScalProd(new IntVar[] {s,e,n,d},
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new int[] {1000,100,10,1});
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IntExpr more = sol.makeScalProd(new IntVar[] {m,o,r,e},
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new int[] {1000,100,10,1});
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IntExpr money = sol.makeScalProd(new IntVar[] {m,o,n,e,y},
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new int[] {10000,1000,100,10,1});
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sol.addConstraint(
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sol.makeEquality(sol.makeSum(send, more).Var(), money.Var()));
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}
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// s > 0
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sol.addConstraint(sol.makeGreater(s, 0));
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// m > 0
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sol.addConstraint(sol.makeGreater(m, 0));
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sol.addConstraint(sol.makeAllDifferent(x, true));
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//
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// Search
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//
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DecisionBuilder db = sol.makePhase(x,
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sol.INT_VAR_DEFAULT,
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sol.INT_VALUE_DEFAULT);
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sol.newSearch(db);
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while (sol.nextSolution()) {
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for(int i = 0; i < 8; i++) {
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System.out.print(x[i].toString() + " ");
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}
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System.out.println();
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}
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sol.endSearch();
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//
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// Statistics
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//
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System.out.println();
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System.out.println("Solutions: " + sol.solutions());
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System.out.println("Failures: " + sol.failures());
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System.out.println("Branches: " + sol.branches());
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System.out.println("Wall time: " + sol.wall_time() + "ms");
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}
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public static void main(String[] args) throws Exception {
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for (int i = 0; i < 5; i++) {
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System.out.println("\nalternative #" + i);
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SendMoreMoney2.solve(i);
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}
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}
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}
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