| 1 | /* |
| 2 | * Copyright (c) 2005 The PseudoQ Project. |
| 3 | * |
| 4 | * This file is part of PseudoQ. |
| 5 | * |
| 6 | * PseudoQ is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU Lesser General Public License as published by |
| 8 | * the Free Software Foundation; either version 2.1 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * PseudoQ is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public License |
| 17 | * along with PseudoQ; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | */ |
| 20 | |
| 21 | package net.sourceforge.pseudoq.solver; |
| 22 | |
| 23 | import java.util.Map; |
| 24 | |
| 25 | import net.sourceforge.pseudoq.model.Coordinate; |
| 26 | import net.sourceforge.pseudoq.model.Grid; |
| 27 | |
| 28 | /** |
| 29 | * Puzzle-solving strategy that checks a super-row for values which are only |
| 30 | * missing from one row. If so, this restricts the possibilities to one box, |
| 31 | * which is checked to see if it has only one unknown cell in that row. |
| 32 | * @author <a href="http://sourceforge.net/users/stevensa">Andrew Stevens</a> |
| 33 | */ |
| 34 | public class ScanRowsStrategy implements Strategy { |
| 35 | /** Log4J logger */ |
| 36 | private static final org.apache.log4j.Logger log = |
| 37 | org.apache.log4j.LogManager.getLogger(ScanRowsStrategy.class); |
| 38 | |
| 39 | private int superRow; |
| 40 | private int value; |
| 41 | private int startRow; |
| 42 | private int endRow; |
| 43 | private Grid grid; |
| 44 | protected Map<String, Counter> counters; |
| 45 | private int startBox; |
| 46 | private int endBox; |
| 47 | private int cellsPerBox; |
| 48 | |
| 49 | /** Creates a new instance of ScanRowsStrategy */ |
| 50 | public ScanRowsStrategy(int superRow, int value, int startRow, int endRow, |
| 51 | Grid grid, Map<String, Counter> counters, int startBox, int endBox, int cellsPerBox) { |
| 52 | log.debug("Initialising ScanRowsStrategy for value " + value + " on SuperRow " + superRow); |
| 53 | this.superRow = superRow; |
| 54 | this.value = value; |
| 55 | this.startRow = startRow; |
| 56 | this.endRow = endRow; |
| 57 | this.grid = grid; |
| 58 | this.counters = counters; |
| 59 | this.startBox = startBox; |
| 60 | this.endBox = endBox; |
| 61 | this.cellsPerBox = cellsPerBox; |
| 62 | } |
| 63 | |
| 64 | public SolutionStep evaluate() |
| 65 | throws ObsoleteStrategyException, UnsolveablePuzzleException |
| 66 | { |
| 67 | SolutionStep nextStep = null; |
| 68 | |
| 69 | if (counterValue("superRowIndicatorCount-" + superRow + "-" + value) == |
| 70 | (endRow - startRow + 1)) { |
| 71 | throw new ObsoleteStrategyException("SuperRow contains all occurrences of value"); |
| 72 | } else if (counterValue("superRowIndicatorCount-" + superRow + "-" + value) == |
| 73 | (endRow - startRow)) { |
| 74 | // find row that doesn't contain the value |
| 75 | for (int row = startRow; row <= endRow; row++) { |
| 76 | if (counterValue("rowIndicatorCount-" + row + "-" + value) == 0) { |
| 77 | if (nextStep != null) { |
| 78 | throw new IllegalStateException("Counter out sync with grid for super-row " + |
| 79 | superRow + ", value " + value); |
| 80 | } |
| 81 | nextStep = checkRow(row); |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | // if ((counterValue("boxIndicatorCount-" + (2 * superRow) + "-" + value) + |
| 86 | // counterValue("boxIndicatorCount-" + ((2 * superRow) + 1) + "-" + value)) != 1) { |
| 87 | // throw new IllegalStateException("Counters out of sync for super-row " + |
| 88 | // superRow + " boxes, value " + value); |
| 89 | // } |
| 90 | |
| 91 | // if (counterValue("rowIndicatorCount-" + row1 + "-" + value) == 0 && |
| 92 | // counterValue("rowIndicatorCount-" + row2 + "-" + value) == 1) { |
| 93 | // nextStep = checkRow(row1); |
| 94 | // } else if (counterValue("rowIndicatorCount-" + row1 + "-" + value) == 1 && |
| 95 | // counterValue("rowIndicatorCount-" + row2 + "-" + value) == 0) { |
| 96 | // nextStep = checkRow(row2); |
| 97 | // } else { |
| 98 | // throw new IllegalStateException("Counter out sync with grid for super-row " + |
| 99 | // superRow + ", value " + value); |
| 100 | // } |
| 101 | } |
| 102 | |
| 103 | return nextStep; |
| 104 | } |
| 105 | |
| 106 | private int counterValue(String counterKey) { |
| 107 | Counter counter = counters.get(counterKey); |
| 108 | if (counter == null) { |
| 109 | throw new IllegalStateException("Counter " + counterKey + " not found."); |
| 110 | } else { |
| 111 | return counter.getCount(); |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | private SolutionStep checkRow(int row) |
| 116 | throws UnsolveablePuzzleException |
| 117 | { |
| 118 | SolutionStep nextStep = null; |
| 119 | |
| 120 | // find box that doesn't contain the value |
| 121 | for (int box = startBox; box <= endBox; box += 1) { |
| 122 | if (counterValue("boxIndicatorCount-" + box + "-" + value) == 0) { |
| 123 | if (nextStep != null) { |
| 124 | throw new IllegalStateException("Counters out of sync for super-row " + |
| 125 | superRow + " boxes, value " + value); |
| 126 | } |
| 127 | nextStep = checkBox(row, box - startBox); |
| 128 | } |
| 129 | } |
| 130 | // if (counterValue("boxIndicatorCount-" + (2 * superRow) + "-" + value) == 1) { |
| 131 | // return checkBox(row, 1); |
| 132 | // } else { |
| 133 | // return checkBox(row, 0); |
| 134 | // } |
| 135 | |
| 136 | return nextStep; |
| 137 | } |
| 138 | |
| 139 | private SolutionStep checkBox(int row, int superColumn) |
| 140 | throws UnsolveablePuzzleException |
| 141 | { |
| 142 | SolutionStep nextStep = null; |
| 143 | int possibles = 0; |
| 144 | |
| 145 | for (int column = cellsPerBox * superColumn; column < cellsPerBox * (superColumn + 1); column++) { |
| 146 | if (grid.get(new Coordinate(row, column)).equals(Integer.valueOf(0)) && |
| 147 | counterValue("columnIndicatorCount-" + column + "-" + value) == 0) { |
| 148 | nextStep = new SolutionStep(new Coordinate(row, column), |
| 149 | value, this.toString()); |
| 150 | possibles++; |
| 151 | } |
| 152 | } |
| 153 | if (possibles == 0) { |
| 154 | throw new UnsolveablePuzzleException(this.toString()); |
| 155 | } else if (possibles > 1) { |
| 156 | nextStep = null; |
| 157 | } |
| 158 | |
| 159 | return nextStep; |
| 160 | } |
| 161 | |
| 162 | public String toString() { |
| 163 | return "ScanRows " + startRow + "-" + endRow + " for " + value; |
| 164 | } |
| 165 | |
| 166 | } |