qcross/libqnono/nonogramsolver.cpp

393 lines
12 KiB
C++

/***************************************************************************
* Copyright (C) 2012 Stefan Bühler <stbuehler@web.de> *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include "nonogramsolver.h"
#include "nonogramimage.h"
#include "nonogramnumbers.h"
#include <QDebug>
namespace libqnono {
struct SolverState {
struct Block {
int minFirst, maxFirst, length;
};
enum Mark { MARK_UNKNOWN = 0, MARK_BLACK, MARK_WHITE };
struct UndoOp {
union {
struct {
int *ptr, old;
} data_int;
struct {
Mark *ptr, old;
} data_mark;
};
enum { UNDO_INT, UNDO_MARK } type;
};
typedef QList<UndoOp> UndoState;
static void trackInt(UndoState *undo_state, bool &changed, int &ptr, int val) {
if (val == ptr) return;
changed = TRUE;
if (undo_state) {
UndoOp op;
op.type = UndoOp::UNDO_INT;
op.data_int.ptr = &ptr;
op.data_int.old = ptr;
undo_state->push_front(op);
}
ptr = val;
}
static void trackMark(UndoState *undo_state, bool &changed, Mark &ptr, Mark val) {
if (val == ptr) return;
changed = TRUE;
if (undo_state) {
UndoOp op;
op.type = UndoOp::UNDO_MARK;
op.data_mark.ptr = &ptr;
op.data_mark.old = ptr;
undo_state->push_front(op);
}
ptr = val;
}
static void undo(UndoState & undo_state) {
foreach (const UndoOp &op, undo_state) {
switch (op.type) {
case UndoOp::UNDO_INT:
*op.data_int.ptr = op.data_int.old;
break;
case UndoOp::UNDO_MARK:
*op.data_mark.ptr = op.data_mark.old;
break;
}
}
undo_state.clear();
}
int nrows, ncols;
QVector< QVector<Block> > rows, cols;
Mark **m_data;
Mark& data(int row, int col) {
return m_data[col][row];
}
template<typename T>
struct View : public T {
View(SolverState *state) : T(state) { }
/* horizontal uses ViewRowColumn, vertical ViewColumnRow */
bool mark(UndoState *undo_state, bool & changed, int m, int from, int to) {
for (int i = from; i <= to; ++i) {
if (this->data(m, i) == MARK_WHITE) return FALSE;
trackMark(undo_state, changed, this->data(m, i), MARK_BLACK);
}
return TRUE;
}
bool clear(UndoState *undo_state, bool & changed, int m, int from, int to) {
for (int i = from; i <= to; ++i) {
if (this->data(m, i) == MARK_BLACK) return FALSE;
trackMark(undo_state, changed, this->data(m, i), MARK_WHITE);
}
return TRUE;
}
bool markBlock(UndoState *undo_state, bool & changed, int m, const Block &b) {
if (b.minFirst == b.maxFirst) {
if (b.minFirst > 0) {
if (this->data(m, b.minFirst-1) == MARK_BLACK) return FALSE;
trackMark(undo_state, changed, this->data(m, b.minFirst-1), MARK_WHITE);
}
if (b.minFirst + b.length < this->dimSecond()) {
if (this->data(m, b.minFirst + b.length) == MARK_BLACK) return FALSE;
trackMark(undo_state, changed, this->data(m, b.minFirst + b.length), MARK_WHITE);
}
}
return mark(undo_state, changed, m, b.maxFirst, b.minFirst+b.length-1);
}
SolverState *state;
};
struct ViewRowColumn {
ViewRowColumn(SolverState *state) : state(state) { }
Mark& data(int row, int col) { return state->data(row, col); }
int dimFirst() const { return state->nrows; }
int dimSecond() const { return state->ncols; }
SolverState *state;
};
struct ViewColumnRow {
ViewColumnRow(SolverState *state) : state(state) { }
Mark& data(int col, int row) { return state->data(row, col); }
int dimFirst() const { return state->ncols; }
int dimSecond() const { return state->nrows; }
SolverState *state;
};
SolverState(const NonogramNumbers & numbers)
: nrows(numbers.height()), ncols(numbers.width()) {
m_data = new Mark*[ncols];
for (int col = 0; col < ncols; ++col) {
m_data[col] = new Mark[nrows];
for (int row = 0; row < nrows; ++row) {
m_data[col][row] = MARK_UNKNOWN;
}
}
rows.resize(nrows);
cols.resize(ncols);
for (int row = 0; row < nrows; ++row) {
foreach (quint16 len, numbers.rows()[row]) {
Block block = { 0, ncols - len, len };
rows[row] << block;
}
}
for (int col = 0; col < ncols; ++col) {
foreach (quint16 len, numbers.columns()[col]) {
Block block = { 0, nrows - len, len };
cols[col] << block;
}
}
}
~SolverState() {
for (int col = 0; col < ncols; ++col) delete [] m_data[col];
delete[] m_data;
}
template<typename T>
bool update(UndoState *undo_state, QVector< QVector<Block> > & lines, View<T> *view, bool & changed) {
for (int i = 0; i < lines.count(); ++i) {
QVector<Block> &line(lines[i]);
int lineLen = line.count();
if (0 == lineLen || (1 == lineLen && 0 == line[0].length)) {
if (!view->clear(undo_state, changed, i, 0, view->dimSecond()-1)) return FALSE;
continue;
}
// first block
{
int cell = line[0].minFirst;
// there must be "length" adjacent non white cells
for (int cell1 = cell, end = cell + line[0].length; cell <= line[0].maxFirst && cell1 < end; ++cell1) {
if (MARK_WHITE == view->data(i, cell1)) {
cell = cell1 + 1;
end = cell + line[0].length;
}
}
if (cell > line[0].minFirst) {
if (cell > line[0].maxFirst) return FALSE; // no solution impossible
trackInt(undo_state, changed, line[0].minFirst, cell);
}
// the first black can't be before the first block
while (cell < line[0].maxFirst && view->data(i, cell) != MARK_BLACK) ++cell;
if (cell < line[0].maxFirst) {
trackInt(undo_state, changed, line[0].maxFirst, cell);
}
}
// last block
{
int len = line.last().length;
int cell = line.last().maxFirst;
// there must be "length" adjacent non white cells
for (int cell1 = cell + len - 1; cell >= line.last().minFirst && cell1 >= cell; --cell1) {
if (MARK_WHITE == view->data(i, cell1)) {
cell = cell1 - len;
}
}
if (cell < line.last().maxFirst) {
if (cell < line.last().minFirst) return FALSE; // no solution impossible
trackInt(undo_state, changed, line.last().maxFirst, cell);
}
// the last black can't be after the last block
while (cell > line.last().minFirst && view->data(i, cell+len-1) != MARK_BLACK) --cell;
if (cell > line.last().minFirst) {
trackInt(undo_state, changed, line.last().minFirst, cell);
}
}
/* check relative block offsets (min distance 1) */
for (int j = 1, k = lineLen - 1; j < lineLen; ++j, --k) {
{
int minFirst = qMax(line[j].minFirst, 1 + line[j-1].minFirst + line[j-1].length);
// the cell before first can't be black
while (minFirst <= line[j].maxFirst && MARK_BLACK == view->data(i, minFirst-1)) ++minFirst;
// there must be "length" adjacent non white cells
for (int cell = minFirst, end = minFirst + line[j].length; minFirst <= line[j].maxFirst && cell < end; ++cell) {
if (MARK_WHITE == view->data(i, cell)) {
minFirst = cell + 1;
end = minFirst + line[j].length;
}
}
if (minFirst >= line[j-1].maxFirst + line[j-1].length) {
int cell = minFirst;
// next black cell can't be before this block
while (cell < line[j].maxFirst && view->data(i, cell) != MARK_BLACK) ++cell;
if (cell < line[j].maxFirst) {
trackInt(undo_state, changed, line[j].maxFirst, cell);
}
}
if (minFirst > line[j].minFirst) {
if (minFirst > line[j].maxFirst) return FALSE; // no solution impossible
trackInt(undo_state, changed, line[j].minFirst, minFirst);
}
}
{
int len = line[k-1].length;
int maxFirst = qMin(line[k-1].maxFirst, line[k].maxFirst - len - 1);
// the cell after last can't be black
while (maxFirst >= line[k-1].minFirst && MARK_BLACK == view->data(i, maxFirst + len)) --maxFirst;
// there must be "length" adjacent non white cells
for (int cell = maxFirst + len - 1; maxFirst >= line[k-1].minFirst && cell >= maxFirst; --cell) {
if (MARK_WHITE == view->data(i, cell)) {
maxFirst = cell - len;
}
}
if (maxFirst + len <= line[k].minFirst) {
int cell = maxFirst;
// next black cell before maxFirst+len can't be after this block
while (cell > line[k-1].minFirst && view->data(i, cell+len-1) != MARK_BLACK) --cell;
if (cell > line[k-1].minFirst) {
trackInt(undo_state, changed, line[k-1].minFirst, cell);
}
}
if (maxFirst < line[k-1].maxFirst) {
if (maxFirst < line[k-1].minFirst) return FALSE; // no solution impossible
trackInt(undo_state, changed, line[k-1].maxFirst, maxFirst);
}
}
}
if (!view->clear(undo_state, changed, i, 0, line[0].minFirst-1)) return FALSE;
for (int j = 0; j < lineLen; ++j) {
if (j > 0 && !view->clear(undo_state, changed, i, line[j-1].maxFirst + line[j-1].length, line[j].minFirst-1)) return FALSE;
if (!view->markBlock(undo_state, changed, i, line[j])) return FALSE;
}
if (!view->clear(undo_state, changed, i, line.last().maxFirst + line.last().length, view->dimSecond()-1)) return FALSE;
}
return TRUE;
}
void storeSolution(NonogramImage & image) {
image.resize(QSize(ncols, nrows));
for (int i = 0; i < ncols; ++i) {
for (int j = 0; j < nrows; ++j) {
image.setPixel(i, j, data(j, i) == MARK_BLACK);
}
}
}
void debugState() {
for (int j = 0; j < nrows; ++j) {
QDebug dbg = qDebug();
for (int i = 0; i < ncols; ++i) {
switch (data(j, i)) {
case MARK_UNKNOWN:
dbg << "?"; break;
case MARK_BLACK:
dbg << "M"; break;
case MARK_WHITE:
dbg << " "; break;
}
}
}
qDebug() << "Row blocks:";
for (int j = 0; j < nrows; ++j) {
QDebug dbg = qDebug() << j << ":";
foreach (Block block, rows[j]) {
dbg << "[" << block.minFirst << block.maxFirst << block.length << "]";
}
}
qDebug() << "Col blocks:";
for (int j = 0; j < ncols; ++j) {
QDebug dbg = qDebug() << j << ":";
foreach (Block block, cols[j]) {
dbg << "[" << block.minFirst << block.maxFirst << block.length << "]";
}
}
}
void solve(QList<NonogramImage> &solutions, UndoState *undo_state = 0) {
bool changed = TRUE;
View<ViewRowColumn> rowColumn(this);
View<ViewColumnRow> columnRow(this);
while (changed) {
changed = FALSE;
if (!update(undo_state, rows, &rowColumn, changed)) return;
if (!update(undo_state, cols, &columnRow, changed)) return;
}
if (!undo_state) {
qDebug() << "State after first run:";
debugState();
}
for (int i = 0; i < ncols; ++i) {
for (int j = 0; j < nrows; ++j) {
if (data(j, i) == MARK_UNKNOWN) {
UndoState subundo;
trackMark(&subundo, changed, data(j, i), MARK_BLACK);
solve(solutions, &subundo);
undo(subundo);
trackMark(&subundo, changed, data(j, i), MARK_WHITE);
solve(solutions, &subundo);
undo(subundo);
return;
}
}
}
qDebug() << "Found solution:";
debugState();
solutions.append(NonogramImage());;
storeSolution(solutions.last());
}
};
QList<NonogramImage> solve(const NonogramNumbers & numbers) {
QList<NonogramImage> solutions;
SolverState solveState(numbers);
solveState.solve(solutions);
foreach(const NonogramImage& solution, solutions) {
Q_ASSERT(numbers.check(solution));
}
return solutions;
}
}