void dlx_search(void) { node_t *column_min, *column, *row, *node; cost++; if (header->right == header) { solutions++; printf("\n%s", grid_cells); } else { column_min = header->right; for (column = column_min->right; column != header; column = column->right) { if (column->rows < column_min->rows) { column_min = column; } } cover_column(column_min); for (row = column_min->bottom; row != column_min; row = row->bottom) { add_piece(row->row_node->piece, row->row_node->grid_origin); for (node = row->right; node != row; node = node->right) { cover_column(node->row_node->column); } dlx_search(); for (node = row->left; node != row; node = node->left) { uncover_column(node->row_node->column); } } uncover_column(column_min); } }
void dlx_search( dlx_t* self, dlx_found_solution_t found_solution ) { dlx_cell_t* c = self->root.right; dlx_cell_t* j; dlx_cell_t* r; if (c == &self->root) { self->num_solutions++; found_solution( self ); } else { for (j=c->right; j!=&self->root; j=j->right) { if (j->size < c->size) c = j; } if (c->size > 0) { dlx_cover( self, c ); for (r=c->down; r!=c; r=r->down) { for (j=r->right; j!=r; j=j->right) { dlx_cover( self, j->column ); } ptrstack_add_last( &self->visit, r ); dlx_search( self, found_solution ); ptrstack_remove_last( &self->visit ); for (j=r->left; j!=r; j=j->left) { dlx_uncover( self, j->column ); } if (self->num_solutions >= self->max_solutions) break; } dlx_uncover( self, c ); } } }
int main(void) { int r; unsigned long grid_cells_n2, pieces_n, pieces_max, column_nodes_n1, column_nodes_n2, row_nodes_n, pieces_r, piece_f, piece_l, nodes_n, i, j, k; scanf("%lu", &grid_rows); if (!grid_rows) { return EXIT_FAILURE; } scanf("%lu", &grid_columns1); if (!grid_columns1) { return EXIT_FAILURE; } grid_cells_n1 = grid_rows*grid_columns1; grid_columns2 = grid_columns1+1; grid_cells_n2 = grid_rows*grid_columns2; grid_cells = malloc(grid_cells_n2+1); if (!grid_cells) { free_data(0UL); return EXIT_FAILURE; } for (i = grid_columns1; i < grid_cells_n2; i += grid_columns2) { grid_cells[i] = '\n'; } grid_cells[grid_cells_n2] = 0; scanf("%lu", &pieces_n); if (!pieces_n) { return EXIT_FAILURE; } pieces_max = pieces_n*8; pieces = malloc(sizeof(piece_t)*pieces_max); if (!pieces) { return EXIT_FAILURE; } column_nodes_n1 = grid_cells_n1+pieces_n; column_nodes_n2 = column_nodes_n1+1; row_nodes_n = 0; pieces_r = 0; for (i = 0; i < pieces_n; i++) { if (!read_piece(&pieces[pieces_r], i)) { free_data(pieces_r); return EXIT_FAILURE; } piece_f = pieces_r; row_nodes_n += pieces[pieces_r].row_nodes_n; pieces_r++; j = 1; do { if (!rotate_piece(&pieces[pieces_r-1], &pieces[pieces_r])) { free_data(pieces_r); return EXIT_FAILURE; } r = compare_pieces(&pieces[piece_f], &pieces[pieces_r]); for (k = piece_f+1; k < pieces_r && !r; k++) { r = compare_pieces(&pieces[k], &pieces[pieces_r]); } if (!r) { row_nodes_n += pieces[pieces_r].row_nodes_n; pieces_r++; j++; } else { free_piece(&pieces[pieces_r]); } } while (j < 4 && !r); piece_l = pieces_r; j = piece_f; do { if (!flip_piece(&pieces[j], &pieces[pieces_r])) { free_data(pieces_r); return EXIT_FAILURE; } r = compare_pieces(&pieces[piece_f], &pieces[pieces_r]); for (k = piece_f+1; k < piece_l && !r; k++) { r = compare_pieces(&pieces[k], &pieces[pieces_r]); } if (!r) { row_nodes_n += pieces[pieces_r].row_nodes_n; pieces_r++; j++; } else { free_piece(&pieces[pieces_r]); } } while (j < piece_l && !r); } row_nodes = malloc(sizeof(row_node_t)*row_nodes_n); if (!row_nodes) { free_data(pieces_r); return EXIT_FAILURE; } nodes_n = column_nodes_n2+row_nodes_n; nodes = malloc(sizeof(node_t)*nodes_n); if (!nodes) { free_data(pieces_r); return EXIT_FAILURE; } for (i = column_nodes_n2; i < nodes_n; i++) { nodes[i].row_node = &row_nodes[i-column_nodes_n2]; } tops = malloc(sizeof(node_t *)*column_nodes_n1); if (!tops) { free_data(pieces_r); return EXIT_FAILURE; } header = &nodes[column_nodes_n1]; set_column_node(nodes, header); for (i = 0; i < column_nodes_n1; i++) { set_column_node(&nodes[i+1], &nodes[i]); tops[i] = &nodes[i]; } row_node = header+1; for (i = 0; i < pieces_r; i++) { print_piece(&pieces[i]); set_piece_row_nodes(&pieces[i]); } for (i = 0; i < column_nodes_n1; i++) { link_top(&nodes[i], tops[i]); } dlx_search(); printf("\nCost %lu\nSolutions %lu\n", cost, solutions); free_data(pieces_r); return EXIT_SUCCESS; }