Files
ortools-clone/examples/contrib/kakuro.cs
2020-11-03 10:15:53 +01:00

204 lines
6.8 KiB
C#

//
// Copyright 2012 Hakan Kjellerstrand
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Google.OrTools.ConstraintSolver;
public class Kakuro
{
/**
* Ensure that the sum of the segments
* in cc == res
*
*/
public static void calc(Solver solver, int[] cc, IntVar[,] x, int res)
{
// ensure that the values are positive
int len = cc.Length / 2;
for (int i = 0; i < len; i++)
{
solver.Add(x[cc[i * 2] - 1, cc[i * 2 + 1] - 1] >= 1);
}
// sum the numbers
solver.Add((from i in Enumerable.Range(0, len) select x[cc[i * 2] - 1, cc[i * 2 + 1] - 1]).ToArray().Sum() ==
res);
}
/**
*
* Kakuru puzzle.
*
* http://en.wikipedia.org/wiki/Kakuro
* """
* The object of the puzzle is to insert a digit from 1 to 9 inclusive
* into each white cell such that the sum of the numbers in each entry
* matches the clue associated with it and that no digit is duplicated in
* any entry. It is that lack of duplication that makes creating Kakuro
* puzzles with unique solutions possible, and which means solving a Kakuro
* puzzle involves investigating combinations more, compared to Sudoku in
* which the focus is on permutations. There is an unwritten rule for
* making Kakuro puzzles that each clue must have at least two numbers
* that add up to it. This is because including one number is mathematically
* trivial when solving Kakuro puzzles; one can simply disregard the
* number entirely and subtract it from the clue it indicates.
* """
*
* This model solves the problem at the Wikipedia page.
* For a larger picture, see
* http://en.wikipedia.org/wiki/File:Kakuro_black_box.svg
*
* The solution:
* 9 7 0 0 8 7 9
* 8 9 0 8 9 5 7
* 6 8 5 9 7 0 0
* 0 6 1 0 2 6 0
* 0 0 4 6 1 3 2
* 8 9 3 1 0 1 4
* 3 1 2 0 0 2 1
*
* Also see http://www.hakank.org/or-tools/kakuro.py
* though this C# model has another representation of
* the problem instance.
*
*/
private static void Solve()
{
Solver solver = new Solver("Kakuro");
// size of matrix
int n = 7;
// segments:
// sum, the segments
// Note: this is 1-based
int[][] problem = { new int[] { 16, 1, 1, 1, 2 },
new int[] { 24, 1, 5, 1, 6, 1, 7 },
new int[] { 17, 2, 1, 2, 2 },
new int[] { 29, 2, 4, 2, 5, 2, 6, 2, 7 },
new int[] { 35, 3, 1, 3, 2, 3, 3, 3, 4, 3, 5 },
new int[] { 7, 4, 2, 4, 3 },
new int[] { 8, 4, 5, 4, 6 },
new int[] { 16, 5, 3, 5, 4, 5, 5, 5, 6, 5, 7 },
new int[] { 21, 6, 1, 6, 2, 6, 3, 6, 4 },
new int[] { 5, 6, 6, 6, 7 },
new int[] { 6, 7, 1, 7, 2, 7, 3 },
new int[] { 3, 7, 6, 7, 7 },
new int[] { 23, 1, 1, 2, 1, 3, 1 },
new int[] { 30, 1, 2, 2, 2, 3, 2, 4, 2 },
new int[] { 27, 1, 5, 2, 5, 3, 5, 4, 5, 5, 5 },
new int[] { 12, 1, 6, 2, 6 },
new int[] { 16, 1, 7, 2, 7 },
new int[] { 17, 2, 4, 3, 4 },
new int[] { 15, 3, 3, 4, 3, 5, 3, 6, 3, 7, 3 },
new int[] { 12, 4, 6, 5, 6, 6, 6, 7, 6 },
new int[] { 7, 5, 4, 6, 4 },
new int[] { 7, 5, 7, 6, 7, 7, 7 },
new int[] { 11, 6, 1, 7, 1 },
new int[] { 10, 6, 2, 7, 2 }
};
int num_p = 24; // Number of segments
// The blanks
// Note: 1-based
int[,] blanks = { { 1, 3 }, { 1, 4 }, { 2, 3 }, { 3, 6 }, { 3, 7 }, { 4, 1 }, { 4, 4 },
{ 4, 7 }, { 5, 1 }, { 5, 2 }, { 6, 5 }, { 7, 4 }, { 7, 5 } };
int num_blanks = blanks.GetLength(0);
//
// Decision variables
//
IntVar[,] x = solver.MakeIntVarMatrix(n, n, 0, 9, "x");
IntVar[] x_flat = x.Flatten();
//
// Constraints
//
// fill the blanks with 0
for (int i = 0; i < num_blanks; i++)
{
solver.Add(x[blanks[i, 0] - 1, blanks[i, 1] - 1] == 0);
}
for (int i = 0; i < num_p; i++)
{
int[] segment = problem[i];
// Remove the sum from the segment
int[] s2 = new int[segment.Length - 1];
for (int j = 1; j < segment.Length; j++)
{
s2[j - 1] = segment[j];
}
// sum this segment
calc(solver, s2, x, segment[0]);
// all numbers in this segment must be distinct
int len = segment.Length / 2;
solver.Add((from j in Enumerable.Range(0, len) select x[s2[j * 2] - 1, s2[j * 2 + 1] - 1])
.ToArray()
.AllDifferent());
}
//
// Search
//
DecisionBuilder db = solver.MakePhase(x_flat, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MIN_VALUE);
solver.NewSearch(db);
while (solver.NextSolution())
{
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
int v = (int)x[i, j].Value();
if (v > 0)
{
Console.Write(v + " ");
}
else
{
Console.Write(" ");
}
}
Console.WriteLine();
}
}
Console.WriteLine("\nSolutions: {0}", solver.Solutions());
Console.WriteLine("WallTime: {0}ms", solver.WallTime());
Console.WriteLine("Failures: {0}", solver.Failures());
Console.WriteLine("Branches: {0} ", solver.Branches());
solver.EndSearch();
}
public static void Main(String[] args)
{
Solve();
}
}