--- /dev/null
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ * Neither the name of "The Computer Language Benchmarks Game" nor the
+ name of "The Computer Language Shootout Benchmarks" nor the names of
+ its contributors may be used to endorse or promote products derived
+ from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Benchmarks Game
+ * http://shootout.alioth.debian.org/
+ *
+ * contributed by Christian Vosteen
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#define TRUE 1
+#define FALSE 0
+
+/* The board is a 50 cell hexagonal pattern. For . . . . .
+ * maximum speed the board will be implemented as . . . . .
+ * 50 bits, which will fit into a 64 bit long long . . . . .
+ * int. . . . . .
+ * . . . . .
+ * I will represent 0's as empty cells and 1's . . . . .
+ * as full cells. . . . . .
+ * . . . . .
+ * . . . . .
+ * . . . . .
+ */
+
+unsigned long long board = 0xFFFC000000000000ULL;
+
+/* The puzzle pieces must be specified by the path followed
+ * from one end to the other along 12 hexagonal directions.
+ *
+ * Piece 0 Piece 1 Piece 2 Piece 3 Piece 4
+ *
+ * O O O O O O O O O O O O O O O
+ * O O O O O O O
+ * O O O
+ *
+ * Piece 5 Piece 6 Piece 7 Piece 8 Piece 9
+ *
+ * O O O O O O O O O O O O O
+ * O O O O O O O O O
+ * O O O
+ *
+ * I had to make it 12 directions because I wanted all of the
+ * piece definitions to fit into the same size arrays. It is
+ * not possible to define piece 4 in terms of the 6 cardinal
+ * directions in 4 moves.
+ */
+
+#define E 0
+#define ESE 1
+#define SE 2
+#define S 3
+#define SW 4
+#define WSW 5
+#define W 6
+#define WNW 7
+#define NW 8
+#define N 9
+#define NE 10
+#define ENE 11
+#define PIVOT 12
+
+char piece_def[10][4] = {
+ { E, E, E, SE},
+ { SE, E, NE, E},
+ { E, E, SE, SW},
+ { E, E, SW, SE},
+ { SE, E, NE, S},
+ { E, E, SW, E},
+ { E, SE, SE, NE},
+ { E, SE, SE, W},
+ { E, SE, E, E},
+ { E, E, E, SW}
+};
+
+
+/* To minimize the amount of work done in the recursive solve function below,
+ * I'm going to allocate enough space for all legal rotations of each piece
+ * at each position on the board. That's 10 pieces x 50 board positions x
+ * 12 rotations. However, not all 12 rotations will fit on every cell, so
+ * I'll have to keep count of the actual number that do.
+ * The pieces are going to be unsigned long long ints just like the board so
+ * they can be bitwise-anded with the board to determine if they fit.
+ * I'm also going to record the next possible open cell for each piece and
+ * location to reduce the burden on the solve function.
+ */
+unsigned long long pieces[10][50][12];
+int piece_counts[10][50];
+char next_cell[10][50][12];
+
+/* Returns the direction rotated 60 degrees clockwise */
+char rotate(char dir) {
+ return (dir + 2) % PIVOT;
+}
+
+/* Returns the direction flipped on the horizontal axis */
+char flip(char dir) {
+ return (PIVOT - dir) % PIVOT;
+}
+
+
+/* Returns the new cell index from the specified cell in the
+ * specified direction. The index is only valid if the
+ * starting cell and direction have been checked by the
+ * out_of_bounds function first.
+ */
+char shift(char cell, char dir) {
+ switch(dir) {
+ case E:
+ return cell + 1;
+ case ESE:
+ if((cell / 5) % 2)
+ return cell + 7;
+ else
+ return cell + 6;
+ case SE:
+ if((cell / 5) % 2)
+ return cell + 6;
+ else
+ return cell + 5;
+ case S:
+ return cell + 10;
+ case SW:
+ if((cell / 5) % 2)
+ return cell + 5;
+ else
+ return cell + 4;
+ case WSW:
+ if((cell / 5) % 2)
+ return cell + 4;
+ else
+ return cell + 3;
+ case W:
+ return cell - 1;
+ case WNW:
+ if((cell / 5) % 2)
+ return cell - 6;
+ else
+ return cell - 7;
+ case NW:
+ if((cell / 5) % 2)
+ return cell - 5;
+ else
+ return cell - 6;
+ case N:
+ return cell - 10;
+ case NE:
+ if((cell / 5) % 2)
+ return cell - 4;
+ else
+ return cell - 5;
+ case ENE:
+ if((cell / 5) % 2)
+ return cell - 3;
+ else
+ return cell - 4;
+ default:
+ return cell;
+ }
+}
+
+/* Returns wether the specified cell and direction will land outside
+ * of the board. Used to determine if a piece is at a legal board
+ * location or not.
+ */
+char out_of_bounds(char cell, char dir) {
+ char i;
+ switch(dir) {
+ case E:
+ return cell % 5 == 4;
+ case ESE:
+ i = cell % 10;
+ return i == 4 || i == 8 || i == 9 || cell >= 45;
+ case SE:
+ return cell % 10 == 9 || cell >= 45;
+ case S:
+ return cell >= 40;
+ case SW:
+ return cell % 10 == 0 || cell >= 45;
+ case WSW:
+ i = cell % 10;
+ return i == 0 || i == 1 || i == 5 || cell >= 45;
+ case W:
+ return cell % 5 == 0;
+ case WNW:
+ i = cell % 10;
+ return i == 0 || i == 1 || i == 5 || cell < 5;
+ case NW:
+ return cell % 10 == 0 || cell < 5;
+ case N:
+ return cell < 10;
+ case NE:
+ return cell % 10 == 9 || cell < 5;
+ case ENE:
+ i = cell % 10;
+ return i == 4 || i == 8 || i == 9 || cell < 5;
+ default:
+ return FALSE;
+ }
+}
+
+/* Rotate a piece 60 degrees clockwise */
+void rotate_piece(int piece) {
+ int i;
+ for(i = 0; i < 4; i++)
+ piece_def[piece][i] = rotate(piece_def[piece][i]);
+}
+
+/* Flip a piece along the horizontal axis */
+void flip_piece(int piece) {
+ int i;
+ for(i = 0; i < 4; i++)
+ piece_def[piece][i] = flip(piece_def[piece][i]);
+}
+
+/* Convenience function to quickly calculate all of the indices for a piece */
+void calc_cell_indices(char *cell, int piece, char index) {
+ cell[0] = index;
+ cell[1] = shift(cell[0], piece_def[piece][0]);
+ cell[2] = shift(cell[1], piece_def[piece][1]);
+ cell[3] = shift(cell[2], piece_def[piece][2]);
+ cell[4] = shift(cell[3], piece_def[piece][3]);
+}
+
+/* Convenience function to quickly calculate if a piece fits on the board */
+int cells_fit_on_board(char *cell, int piece) {
+ return (!out_of_bounds(cell[0], piece_def[piece][0]) &&
+ !out_of_bounds(cell[1], piece_def[piece][1]) &&
+ !out_of_bounds(cell[2], piece_def[piece][2]) &&
+ !out_of_bounds(cell[3], piece_def[piece][3]));
+}
+
+/* Returns the lowest index of the cells of a piece.
+ * I use the lowest index that a piece occupies as the index for looking up
+ * the piece in the solve function.
+ */
+char minimum_of_cells(char *cell) {
+ char minimum = cell[0];
+ minimum = cell[1] < minimum ? cell[1] : minimum;
+ minimum = cell[2] < minimum ? cell[2] : minimum;
+ minimum = cell[3] < minimum ? cell[3] : minimum;
+ minimum = cell[4] < minimum ? cell[4] : minimum;
+ return minimum;
+}
+
+/* Calculate the lowest possible open cell if the piece is placed on the board.
+ * Used to later reduce the amount of time searching for open cells in the
+ * solve function.
+ */
+char first_empty_cell(char *cell, char minimum) {
+ char first_empty = minimum;
+ while(first_empty == cell[0] || first_empty == cell[1] ||
+ first_empty == cell[2] || first_empty == cell[3] ||
+ first_empty == cell[4])
+ first_empty++;
+ return first_empty;
+}
+
+/* Generate the unsigned long long int that will later be anded with the
+ * board to determine if it fits.
+ */
+unsigned long long bitmask_from_cells(char *cell) {
+ unsigned long long piece_mask = 0ULL;
+ int i;
+ for(i = 0; i < 5; i++)
+ piece_mask |= 1ULL << cell[i];
+ return piece_mask;
+}
+
+/* Record the piece and other important information in arrays that will
+ * later be used by the solve function.
+ */
+void record_piece(int piece, int minimum, char first_empty,
+ unsigned long long piece_mask) {
+ pieces[piece][minimum][piece_counts[piece][minimum]] = piece_mask;
+ next_cell[piece][minimum][piece_counts[piece][minimum]] = first_empty;
+ piece_counts[piece][minimum]++;
+}
+
+
+/* Fill the entire board going cell by cell. If any cells are "trapped"
+ * they will be left alone.
+ */
+void fill_contiguous_space(char *board, int index) {
+ if(board[index] == 1)
+ return;
+ board[index] = 1;
+ if(!out_of_bounds(index, E))
+ fill_contiguous_space(board, shift(index, E));
+ if(!out_of_bounds(index, SE))
+ fill_contiguous_space(board, shift(index, SE));
+ if(!out_of_bounds(index, SW))
+ fill_contiguous_space(board, shift(index, SW));
+ if(!out_of_bounds(index, W))
+ fill_contiguous_space(board, shift(index, W));
+ if(!out_of_bounds(index, NW))
+ fill_contiguous_space(board, shift(index, NW));
+ if(!out_of_bounds(index, NE))
+ fill_contiguous_space(board, shift(index, NE));
+}
+
+
+/* To thin the number of pieces, I calculate if any of them trap any empty
+ * cells at the edges. There are only a handful of exceptions where the
+ * the board can be solved with the trapped cells. For example: piece 8 can
+ * trap 5 cells in the corner, but piece 3 can fit in those cells, or piece 0
+ * can split the board in half where both halves are viable.
+ */
+int has_island(char *cell, int piece) {
+ char temp_board[50];
+ char c;
+ int i;
+ for(i = 0; i < 50; i++)
+ temp_board[i] = 0;
+ for(i = 0; i < 5; i++)
+ temp_board[((int)cell[i])] = 1;
+ i = 49;
+ while(temp_board[i] == 1)
+ i--;
+ fill_contiguous_space(temp_board, i);
+ c = 0;
+ for(i = 0; i < 50; i++)
+ if(temp_board[i] == 0)
+ c++;
+ if(c == 0 || (c == 5 && piece == 8) || (c == 40 && piece == 8) ||
+ (c % 5 == 0 && piece == 0))
+ return FALSE;
+ else
+ return TRUE;
+}
+
+
+/* Calculate all six rotations of the specified piece at the specified index.
+ * We calculate only half of piece 3's rotations. This is because any solution
+ * found has an identical solution rotated 180 degrees. Thus we can reduce the
+ * number of attempted pieces in the solve algorithm by not including the 180-
+ * degree-rotated pieces of ONE of the pieces. I chose piece 3 because it gave
+ * me the best time ;)
+ */
+ void calc_six_rotations(char piece, char index) {
+ char rotation, cell[5];
+ char minimum, first_empty;
+ unsigned long long piece_mask;
+
+ for(rotation = 0; rotation < 6; rotation++) {
+ if(piece != 3 || rotation < 3) {
+ calc_cell_indices(cell, piece, index);
+ if(cells_fit_on_board(cell, piece) && !has_island(cell, piece)) {
+ minimum = minimum_of_cells(cell);
+ first_empty = first_empty_cell(cell, minimum);
+ piece_mask = bitmask_from_cells(cell);
+ record_piece(piece, minimum, first_empty, piece_mask);
+ }
+ }
+ rotate_piece(piece);
+ }
+}
+
+/* Calculate every legal rotation for each piece at each board location. */
+void calc_pieces(void) {
+ char piece, index;
+
+ for(piece = 0; piece < 10; piece++) {
+ for(index = 0; index < 50; index++) {
+ calc_six_rotations(piece, index);
+ flip_piece(piece);
+ calc_six_rotations(piece, index);
+ }
+ }
+}
+
+
+
+/* Calculate all 32 possible states for a 5-bit row and all rows that will
+ * create islands that follow any of the 32 possible rows. These pre-
+ * calculated 5-bit rows will be used to find islands in a partially solved
+ * board in the solve function.
+ */
+#define ROW_MASK 0x1F
+#define TRIPLE_MASK 0x7FFF
+char all_rows[32] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31};
+int bad_even_rows[32][32];
+int bad_odd_rows[32][32];
+int bad_even_triple[32768];
+int bad_odd_triple[32768];
+
+int rows_bad(char row1, char row2, int even) {
+ /* even is referring to row1 */
+ int i, in_zeroes, group_okay;
+ char block, row2_shift;
+ /* Test for blockages at same index and shifted index */
+ if(even)
+ row2_shift = ((row2 << 1) & ROW_MASK) | 0x01;
+ else
+ row2_shift = (row2 >> 1) | 0x10;
+ block = ((row1 ^ row2) & row2) & ((row1 ^ row2_shift) & row2_shift);
+ /* Test for groups of 0's */
+ in_zeroes = FALSE;
+ group_okay = FALSE;
+ for(i = 0; i < 5; i++) {
+ if(row1 & (1 << i)) {
+ if(in_zeroes) {
+ if(!group_okay)
+ return TRUE;
+ in_zeroes = FALSE;
+ group_okay = FALSE;
+ }
+ } else {
+ if(!in_zeroes)
+ in_zeroes = TRUE;
+ if(!(block & (1 << i)))
+ group_okay = TRUE;
+ }
+ }
+ if(in_zeroes)
+ return !group_okay;
+ else
+ return FALSE;
+}
+
+/* Check for cases where three rows checked sequentially cause a false
+ * positive. One scenario is when 5 cells may be surrounded where piece 5
+ * or 7 can fit. The other scenario is when piece 2 creates a hook shape.
+ */
+int triple_is_okay(char row1, char row2, char row3, int even) {
+ if(even) {
+ /* There are four cases:
+ * row1: 00011 00001 11001 10101
+ * row2: 01011 00101 10001 10001
+ * row3: 011?? 00110 ????? ?????
+ */
+ return ((row1 == 0x03) && (row2 == 0x0B) && ((row3 & 0x1C) == 0x0C)) ||
+ ((row1 == 0x01) && (row2 == 0x05) && (row3 == 0x06)) ||
+ ((row1 == 0x19) && (row2 == 0x11)) ||
+ ((row1 == 0x15) && (row2 == 0x11));
+ } else {
+ /* There are two cases:
+ * row1: 10011 10101
+ * row2: 10001 10001
+ * row3: ????? ?????
+ */
+ return ((row1 == 0x13) && (row2 == 0x11)) ||
+ ((row1 == 0x15) && (row2 == 0x11));
+ }
+}
+
+
+void calc_rows(void) {
+ int row1, row2, row3;
+ int result1, result2;
+ for(row1 = 0; row1 < 32; row1++) {
+ for(row2 = 0; row2 < 32; row2++) {
+ bad_even_rows[row1][row2] = rows_bad(row1, row2, TRUE);
+ bad_odd_rows[row1][row2] = rows_bad(row1, row2, FALSE);
+ }
+ }
+ for(row1 = 0; row1 < 32; row1++) {
+ for(row2 = 0; row2 < 32; row2++) {
+ for(row3 = 0; row3 < 32; row3++) {
+ result1 = bad_even_rows[row1][row2];
+ result2 = bad_odd_rows[row2][row3];
+ if(result1 == FALSE && result2 == TRUE
+ && triple_is_okay(row1, row2, row3, TRUE))
+ bad_even_triple[row1+(row2*32)+(row3*1024)] = FALSE;
+ else
+ bad_even_triple[row1+(row2*32)+(row3*1024)] = result1 || result2;
+
+ result1 = bad_odd_rows[row1][row2];
+ result2 = bad_even_rows[row2][row3];
+ if(result1 == FALSE && result2 == TRUE
+ && triple_is_okay(row1, row2, row3, FALSE))
+ bad_odd_triple[row1+(row2*32)+(row3*1024)] = FALSE;
+ else
+ bad_odd_triple[row1+(row2*32)+(row3*1024)] = result1 || result2;
+ }
+ }
+ }
+}
+
+
+
+/* Calculate islands while solving the board.
+ */
+int boardHasIslands(char cell) {
+ /* Too low on board, don't bother checking */
+ if(cell >= 40)
+ return FALSE;
+ int current_triple = (board >> ((cell / 5) * 5)) & TRIPLE_MASK;
+ if((cell / 5) % 2)
+ return bad_odd_triple[current_triple];
+ else
+ return bad_even_triple[current_triple];
+}
+
+
+/* The recursive solve algorithm. Try to place each permutation in the upper-
+ * leftmost empty cell. Mark off available pieces as it goes along.
+ * Because the board is a bit mask, the piece number and bit mask must be saved
+ * at each successful piece placement. This data is used to create a 50 char
+ * array if a solution is found.
+ */
+short avail = 0x03FF;
+char sol_nums[10];
+unsigned long long sol_masks[10];
+signed char solutions[2100][50];
+int solution_count = 0;
+int max_solutions = 2100;
+
+void record_solution(void) {
+ int sol_no, index;
+ unsigned long long sol_mask;
+ for(sol_no = 0; sol_no < 10; sol_no++) {
+ sol_mask = sol_masks[sol_no];
+ for(index = 0; index < 50; index++) {
+ if(sol_mask & 1ULL) {
+ solutions[solution_count][index] = sol_nums[sol_no];
+ /* Board rotated 180 degrees is a solution too! */
+ solutions[solution_count+1][49-index] = sol_nums[sol_no];
+ }
+ sol_mask = sol_mask >> 1;
+ }
+ }
+ solution_count += 2;
+}
+
+void solve(int depth, int cell) {
+ int piece, rotation, max_rots;
+ unsigned long long *piece_mask;
+ short piece_no_mask;
+
+ if(solution_count >= max_solutions)
+ return;
+
+ while(board & (1ULL << cell))
+ cell++;
+
+ for(piece = 0; piece < 10; piece++) {
+ piece_no_mask = 1 << piece;
+ if(!(avail & piece_no_mask))
+ continue;
+ avail ^= piece_no_mask;
+ max_rots = piece_counts[piece][cell];
+ piece_mask = pieces[piece][cell];
+ for(rotation = 0; rotation < max_rots; rotation++) {
+ if(!(board & *(piece_mask + rotation))) {
+ sol_nums[depth] = piece;
+ sol_masks[depth] = *(piece_mask + rotation);
+ if(depth == 9) {
+ /* Solution found!!!!!11!!ONE! */
+ record_solution();
+ avail ^= piece_no_mask;
+ return;
+ }
+ board |= *(piece_mask + rotation);
+ if(!boardHasIslands(next_cell[piece][cell][rotation]))
+ solve(depth + 1, next_cell[piece][cell][rotation]);
+ board ^= *(piece_mask + rotation);
+ }
+ }
+ avail ^= piece_no_mask;
+ }
+}
+
+
+/* qsort comparator - used to find first and last solutions */
+int solution_sort(const void *elem1, const void *elem2) {
+ signed char *char1 = (signed char *) elem1;
+ signed char *char2 = (signed char *) elem2;
+ int i = 0;
+ while(i < 50 && char1[i] == char2[i])
+ i++;
+ return char1[i] - char2[i];
+}
+
+
+/* pretty print a board in the specified hexagonal format */
+void pretty(signed char *b) {
+ int i;
+ for(i = 0; i < 50; i += 10) {
+ printf("%c %c %c %c %c \n %c %c %c %c %c \n", b[i]+'0', b[i+1]+'0',
+ b[i+2]+'0', b[i+3]+'0', b[i+4]+'0', b[i+5]+'0', b[i+6]+'0',
+ b[i+7]+'0', b[i+8]+'0', b[i+9]+'0');
+ }
+ printf("\n");
+}
+
+int main(int argc, char **argv) {
+ if(argc > 1)
+ max_solutions = atoi(argv[1]);
+ calc_pieces();
+ calc_rows();
+ solve(0, 0);
+ printf("%d solutions found\n\n", solution_count);
+ qsort(solutions, solution_count, 50 * sizeof(signed char), solution_sort);
+ pretty(solutions[0]);
+ pretty(solutions[solution_count-1]);
+ return 0;
+}
--- /dev/null
+/*
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ * Neither the name of "The Computer Language Benchmarks Game" nor the
+ name of "The Computer Language Shootout Benchmarks" nor the names of
+ its contributors may be used to endorse or promote products derived
+ from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* The Computer Language Benchmarks Game
+ * http://shootout.alioth.debian.org/
+ *
+ * contributed by The Go Authors.
+ * based on meteor-contest.c by Christian Vosteen
+ */
+
+package main
+
+import (
+ "flag";
+ "fmt";
+)
+
+var max_solutions = flag.Int("n", 2100, "maximum number of solutions")
+
+
+func boolInt(b bool) int8 {
+ if b {
+ return 1
+ }
+ return 0
+}
+
+/* The board is a 50 cell hexagonal pattern. For . . . . .
+ * maximum speed the board will be implemented as . . . . .
+ * 50 bits, which will fit into a 64 bit long long . . . . .
+ * int. . . . . .
+ * . . . . .
+ * I will represent 0's as empty cells and 1's . . . . .
+ * as full cells. . . . . .
+ * . . . . .
+ * . . . . .
+ * . . . . .
+ */
+
+var board uint64 = 0xFFFC000000000000
+
+/* The puzzle pieces must be specified by the path followed
+ * from one end to the other along 12 hexagonal directions.
+ *
+ * Piece 0 Piece 1 Piece 2 Piece 3 Piece 4
+ *
+ * O O O O O O O O O O O O O O O
+ * O O O O O O O
+ * O O O
+ *
+ * Piece 5 Piece 6 Piece 7 Piece 8 Piece 9
+ *
+ * O O O O O O O O O O O O O
+ * O O O O O O O O O
+ * O O O
+ *
+ * I had to make it 12 directions because I wanted all of the
+ * piece definitions to fit into the same size arrays. It is
+ * not possible to define piece 4 in terms of the 6 cardinal
+ * directions in 4 moves.
+ */
+
+const (
+ E = iota;
+ ESE;
+ SE;
+ S;
+ SW;
+ WSW;
+ W;
+ WNW;
+ NW;
+ N;
+ NE;
+ ENE;
+ PIVOT;
+)
+
+var piece_def = [10][4]int8 {
+ [4]int8{ E, E, E, SE},
+ [4]int8{ SE, E, NE, E},
+ [4]int8{ E, E, SE, SW},
+ [4]int8{ E, E, SW, SE},
+ [4]int8{ SE, E, NE, S},
+ [4]int8{ E, E, SW, E},
+ [4]int8{ E, SE, SE, NE},
+ [4]int8{ E, SE, SE, W},
+ [4]int8{ E, SE, E, E},
+ [4]int8{ E, E, E, SW}
+}
+
+
+/* To minimize the amount of work done in the recursive solve function below,
+ * I'm going to allocate enough space for all legal rotations of each piece
+ * at each position on the board. That's 10 pieces x 50 board positions x
+ * 12 rotations. However, not all 12 rotations will fit on every cell, so
+ * I'll have to keep count of the actual number that do.
+ * The pieces are going to be unsigned long long ints just like the board so
+ * they can be bitwise-anded with the board to determine if they fit.
+ * I'm also going to record the next possible open cell for each piece and
+ * location to reduce the burden on the solve function.
+ */
+var (
+ pieces[10][50][12] uint64;
+ piece_counts[10][50] int;
+ next_cell[10][50][12] int8;
+)
+
+/* Returns the direction rotated 60 degrees clockwise */
+func rotate(dir int8) int8 {
+ return (dir + 2) % PIVOT;
+}
+
+/* Returns the direction flipped on the horizontal axis */
+func flip(dir int8) int8 {
+ return (PIVOT - dir) % PIVOT;
+}
+
+
+/* Returns the new cell index from the specified cell in the
+ * specified direction. The index is only valid if the
+ * starting cell and direction have been checked by the
+ * out_of_bounds function first.
+ */
+func shift(cell, dir int8) int8 {
+ switch dir {
+ case E:
+ return cell + 1;
+ case ESE:
+ if ((cell / 5) % 2) != 0 {
+ return cell + 7;
+ } else {
+ return cell + 6;
+ }
+ case SE:
+ if ((cell / 5) % 2) != 0 {
+ return cell + 6;
+ } else {
+ return cell + 5;
+ }
+ case S:
+ return cell + 10;
+ case SW:
+ if ((cell / 5) % 2) != 0 {
+ return cell + 5;
+ } else {
+ return cell + 4;
+ }
+ case WSW:
+ if ((cell / 5) % 2) != 0 {
+ return cell + 4;
+ } else {
+ return cell + 3;
+ }
+ case W:
+ return cell - 1;
+ case WNW:
+ if ((cell / 5) % 2) != 0{
+ return cell - 6;
+ } else {
+ return cell - 7;
+ }
+ case NW:
+ if ((cell / 5) % 2) != 0{
+ return cell - 5;
+ } else {
+ return cell - 6;
+ }
+ case N:
+ return cell - 10;
+ case NE:
+ if ((cell / 5) % 2) != 0{
+ return cell - 4;
+ } else {
+ return cell - 5;
+ }
+ case ENE:
+ if ((cell / 5) % 2) != 0{
+ return cell - 3;
+ } else {
+ return cell - 4;
+ }
+ }
+ return cell;
+}
+
+/* Returns wether the specified cell and direction will land outside
+ * of the board. Used to determine if a piece is at a legal board
+ * location or not.
+ */
+func out_of_bounds(cell, dir int8) bool {
+ switch(dir) {
+ case E:
+ return cell % 5 == 4;
+ case ESE:
+ i := cell % 10;
+ return i == 4 || i == 8 || i == 9 || cell >= 45;
+ case SE:
+ return cell % 10 == 9 || cell >= 45;
+ case S:
+ return cell >= 40;
+ case SW:
+ return cell % 10 == 0 || cell >= 45;
+ case WSW:
+ i := cell % 10;
+ return i == 0 || i == 1 || i == 5 || cell >= 45;
+ case W:
+ return cell % 5 == 0;
+ case WNW:
+ i := cell % 10;
+ return i == 0 || i == 1 || i == 5 || cell < 5;
+ case NW:
+ return cell % 10 == 0 || cell < 5;
+ case N:
+ return cell < 10;
+ case NE:
+ return cell % 10 == 9 || cell < 5;
+ case ENE:
+ i := cell % 10;
+ return i == 4 || i == 8 || i == 9 || cell < 5;
+ }
+ return false;
+}
+
+/* Rotate a piece 60 degrees clockwise */
+func rotate_piece(piece int) {
+ for i := 0; i < 4; i++ {
+ piece_def[piece][i] = rotate(piece_def[piece][i]);
+ }
+}
+
+/* Flip a piece along the horizontal axis */
+func flip_piece(piece int) {
+ for i := 0; i < 4; i++ {
+ piece_def[piece][i] = flip(piece_def[piece][i]);
+ }
+}
+
+/* Convenience function to quickly calculate all of the indices for a piece */
+func calc_cell_indices(cell []int8, piece int, index int8) {
+ cell[0] = index;
+ for i := 1; i < 5; i++ {
+ cell[i] = shift(cell[i-1], piece_def[piece][i-1]);
+ }
+}
+
+/* Convenience function to quickly calculate if a piece fits on the board */
+func cells_fit_on_board(cell []int8, piece int) bool {
+ return !out_of_bounds(cell[0], piece_def[piece][0]) &&
+ !out_of_bounds(cell[1], piece_def[piece][1]) &&
+ !out_of_bounds(cell[2], piece_def[piece][2]) &&
+ !out_of_bounds(cell[3], piece_def[piece][3]);
+}
+
+/* Returns the lowest index of the cells of a piece.
+ * I use the lowest index that a piece occupies as the index for looking up
+ * the piece in the solve function.
+ */
+func minimum_of_cells(cell []int8) int8 {
+ minimum := cell[0];
+ for i := 1; i < 5; i++ {
+ if cell[i] < minimum {
+ minimum = cell[i]
+ }
+ }
+ return minimum;
+}
+
+/* Calculate the lowest possible open cell if the piece is placed on the board.
+ * Used to later reduce the amount of time searching for open cells in the
+ * solve function.
+ */
+func first_empty_cell(cell []int8, minimum int8) int8 {
+ first_empty := minimum;
+ for first_empty == cell[0] || first_empty == cell[1] ||
+ first_empty == cell[2] || first_empty == cell[3] ||
+ first_empty == cell[4] {
+ first_empty++;
+ }
+ return first_empty;
+}
+
+/* Generate the unsigned long long int that will later be anded with the
+ * board to determine if it fits.
+ */
+func bitmask_from_cells(cell []int8) uint64 {
+ var piece_mask uint64;
+ for i := 0; i < 5; i++ {
+ piece_mask |= 1 << uint(cell[i]);
+ }
+ return piece_mask;
+}
+
+/* Record the piece and other important information in arrays that will
+ * later be used by the solve function.
+ */
+func record_piece(piece int, minimum int8, first_empty int8, piece_mask uint64) {
+ pieces[piece][minimum][piece_counts[piece][minimum]] = piece_mask;
+ next_cell[piece][minimum][piece_counts[piece][minimum]] = first_empty;
+ piece_counts[piece][minimum]++;
+}
+
+
+/* Fill the entire board going cell by cell. If any cells are "trapped"
+ * they will be left alone.
+ */
+func fill_contiguous_space(board []int8, index int8) {
+ if board[index] == 1 {
+ return;
+ }
+ board[index] = 1;
+ if !out_of_bounds(index, E) {
+ fill_contiguous_space(board, shift(index, E));
+ }
+ if !out_of_bounds(index, SE) {
+ fill_contiguous_space(board, shift(index, SE));
+ }
+ if !out_of_bounds(index, SW) {
+ fill_contiguous_space(board, shift(index, SW));
+ }
+ if !out_of_bounds(index, W) {
+ fill_contiguous_space(board, shift(index, W));
+ }
+ if !out_of_bounds(index, NW) {
+ fill_contiguous_space(board, shift(index, NW));
+ }
+ if !out_of_bounds(index, NE) {
+ fill_contiguous_space(board, shift(index, NE));
+ }
+}
+
+
+/* To thin the number of pieces, I calculate if any of them trap any empty
+ * cells at the edges. There are only a handful of exceptions where the
+ * the board can be solved with the trapped cells. For example: piece 8 can
+ * trap 5 cells in the corner, but piece 3 can fit in those cells, or piece 0
+ * can split the board in half where both halves are viable.
+ */
+func has_island(cell []int8, piece int) bool {
+ temp_board := make([]int8, 50);
+ var i int;
+ for i = 0; i < 5; i++ {
+ temp_board[cell[i]] = 1;
+ }
+ i = 49;
+ for temp_board[i] == 1 {
+ i--;
+ }
+ fill_contiguous_space(temp_board, int8(i));
+ c := 0;
+ for i = 0; i < 50; i++ {
+ if temp_board[i] == 0 {
+ c++;
+ }
+ }
+ if c == 0 || (c == 5 && piece == 8) || (c == 40 && piece == 8) ||
+ (c % 5 == 0 && piece == 0) {
+ return false;
+ }
+ return true;
+}
+
+
+/* Calculate all six rotations of the specified piece at the specified index.
+ * We calculate only half of piece 3's rotations. This is because any solution
+ * found has an identical solution rotated 180 degrees. Thus we can reduce the
+ * number of attempted pieces in the solve algorithm by not including the 180-
+ * degree-rotated pieces of ONE of the pieces. I chose piece 3 because it gave
+ * me the best time ;)
+ */
+func calc_six_rotations(piece, index int) {
+ cell := make([]int8, 5);
+ for rotation := 0; rotation < 6; rotation++ {
+ if piece != 3 || rotation < 3 {
+ calc_cell_indices(cell, piece, int8(index));
+ if cells_fit_on_board(cell, piece) && !has_island(cell, piece) {
+ minimum := minimum_of_cells(cell);
+ first_empty := first_empty_cell(cell, minimum);
+ piece_mask := bitmask_from_cells(cell);
+ record_piece(piece, minimum, first_empty, piece_mask);
+ }
+ }
+ rotate_piece(piece);
+ }
+}
+
+/* Calculate every legal rotation for each piece at each board location. */
+func calc_pieces() {
+ for piece := 0; piece < 10; piece++ {
+ for index := 0; index < 50; index++ {
+ calc_six_rotations(piece, index);
+ flip_piece(piece);
+ calc_six_rotations(piece, index);
+ }
+ }
+}
+
+
+
+/* Calculate all 32 possible states for a 5-bit row and all rows that will
+ * create islands that follow any of the 32 possible rows. These pre-
+ * calculated 5-bit rows will be used to find islands in a partially solved
+ * board in the solve function.
+ */
+ const (
+ ROW_MASK = 0x1F;
+ TRIPLE_MASK = 0x7FFF;
+)
+var (
+ all_rows = [32]int8{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+ 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31};
+ bad_even_rows [32][32]int8;
+ bad_odd_rows [32][32]int8;
+ bad_even_triple [32768]int8;
+ bad_odd_triple [32768]int8;
+)
+
+func rows_bad(row1, row2 int8, even bool) int8 {
+ /* even is referring to row1 */
+ var row2_shift int8;
+ /* Test for blockages at same index and shifted index */
+ if even {
+ row2_shift = ((row2 << 1) & ROW_MASK) | 0x01;
+ } else {
+ row2_shift = (row2 >> 1) | 0x10;
+ }
+ block := ((row1 ^ row2) & row2) & ((row1 ^ row2_shift) & row2_shift);
+ /* Test for groups of 0's */
+ in_zeroes := false;
+ group_okay := false;
+ for i := uint8(0); i < 5; i++ {
+ if row1 & (1 << i) != 0 {
+ if in_zeroes {
+ if !group_okay {
+ return 1;
+ }
+ in_zeroes = false;
+ group_okay = false;
+ }
+ } else {
+ if !in_zeroes {
+ in_zeroes = true;
+ }
+ if (block & (1 << i)) == 0 {
+ group_okay = true;
+ }
+ }
+ }
+ if in_zeroes {
+ return boolInt(!group_okay);
+ }
+ return 0;
+}
+
+/* Check for cases where three rows checked sequentially cause a false
+ * positive. One scenario is when 5 cells may be surrounded where piece 5
+ * or 7 can fit. The other scenario is when piece 2 creates a hook shape.
+ */
+func triple_is_okay(row1, row2, row3 int, even bool) bool {
+ if even {
+ /* There are four cases:
+ * row1: 00011 00001 11001 10101
+ * row2: 01011 00101 10001 10001
+ * row3: 011?? 00110 ????? ?????
+ */
+ return ((row1 == 0x03) && (row2 == 0x0B) && ((row3 & 0x1C) == 0x0C)) ||
+ ((row1 == 0x01) && (row2 == 0x05) && (row3 == 0x06)) ||
+ ((row1 == 0x19) && (row2 == 0x11)) ||
+ ((row1 == 0x15) && (row2 == 0x11));
+ }
+ /* There are two cases:
+ * row1: 10011 10101
+ * row2: 10001 10001
+ * row3: ????? ?????
+ */
+ return ((row1 == 0x13) && (row2 == 0x11)) ||
+ ((row1 == 0x15) && (row2 == 0x11));
+}
+
+func calc_rows() {
+ for row1 := int8(0); row1 < 32; row1++ {
+ for row2 := int8(0); row2 < 32; row2++ {
+ bad_even_rows[row1][row2] = rows_bad(row1, row2, true);
+ bad_odd_rows[row1][row2] = rows_bad(row1, row2, false);
+ }
+ }
+ for row1 := 0; row1 < 32; row1++ {
+ for row2 := 0; row2 < 32; row2++ {
+ for row3 := 0; row3 < 32; row3++ {
+ result1 := bad_even_rows[row1][row2];
+ result2 := bad_odd_rows[row2][row3];
+ if result1==0 && result2!=0 && triple_is_okay(row1, row2, row3, true) {
+ bad_even_triple[row1+(row2*32)+(row3*1024)] = 0;
+ } else {
+ bad_even_triple[row1+(row2*32)+(row3*1024)] = boolInt(result1!=0 || result2!=0);
+ }
+
+ result1 = bad_odd_rows[row1][row2];
+ result2 = bad_even_rows[row2][row3];
+ if result1==0 && result2!=0 && triple_is_okay(row1, row2, row3, false) {
+ bad_odd_triple[row1+(row2*32)+(row3*1024)] = 0;
+ } else {
+ bad_odd_triple[row1+(row2*32)+(row3*1024)] = boolInt(result1!=0 || result2!=0);
+ }
+ }
+ }
+ }
+}
+
+
+
+/* Calculate islands while solving the board.
+ */
+func boardHasIslands(cell int8) int8 {
+ /* Too low on board, don't bother checking */
+ if cell >= 40 {
+ return 0;
+ }
+ current_triple := (board >> uint((cell / 5) * 5)) & TRIPLE_MASK;
+ if (cell / 5) % 2 != 0 {
+ return bad_odd_triple[current_triple];
+ }
+ return bad_even_triple[current_triple];
+}
+
+
+/* The recursive solve algorithm. Try to place each permutation in the upper-
+ * leftmost empty cell. Mark off available pieces as it goes along.
+ * Because the board is a bit mask, the piece number and bit mask must be saved
+ * at each successful piece placement. This data is used to create a 50 char
+ * array if a solution is found.
+ */
+var (
+ avail uint16 = 0x03FF;
+ sol_nums [10]int8;
+ sol_masks [10]uint64;
+ solutions [2100][50]int8;
+ solution_count = 0;
+)
+
+func record_solution() {
+ for sol_no := 0; sol_no < 10; sol_no++ {
+ sol_mask := sol_masks[sol_no];
+ for index := 0; index < 50; index++ {
+ if sol_mask & 1 == 1 {
+ solutions[solution_count][index] = sol_nums[sol_no];
+ /* Board rotated 180 degrees is a solution too! */
+ solutions[solution_count+1][49-index] = sol_nums[sol_no];
+ }
+ sol_mask = sol_mask >> 1;
+ }
+ }
+ solution_count += 2;
+}
+
+func solve(depth, cell int8) {
+ if solution_count >= *max_solutions {
+ return;
+ }
+
+ for board & (1 << uint(cell)) != 0 {
+ cell++;
+ }
+
+ for piece := int8(0); piece < 10; piece++ {
+ var piece_no_mask uint16 = 1 << uint(piece);
+ if avail & piece_no_mask == 0 {
+ continue;
+ }
+ avail ^= piece_no_mask;
+ max_rots := piece_counts[piece][cell];
+ piece_mask := pieces[piece][cell];
+ for rotation := 0; rotation < max_rots; rotation++ {
+ if board & piece_mask[rotation] == 0 {
+ sol_nums[depth] = piece;
+ sol_masks[depth] = piece_mask[rotation];
+ if depth == 9 {
+ /* Solution found!!!!!11!!ONE! */
+ record_solution();
+ avail ^= piece_no_mask;
+ return;
+ }
+ board |= piece_mask[rotation];
+ if boardHasIslands(next_cell[piece][cell][rotation]) == 0 {
+ solve(depth + 1, next_cell[piece][cell][rotation]);
+ }
+ board ^= piece_mask[rotation];
+ }
+ }
+ avail ^= piece_no_mask;
+ }
+}
+
+/* pretty print a board in the specified hexagonal format */
+func pretty(b *[50]int8) {
+ for i := 0; i < 50; i += 10 {
+ fmt.Printf("%c %c %c %c %c \n %c %c %c %c %c \n", b[i]+'0', b[i+1]+'0',
+ b[i+2]+'0', b[i+3]+'0', b[i+4]+'0', b[i+5]+'0', b[i+6]+'0',
+ b[i+7]+'0', b[i+8]+'0', b[i+9]+'0');
+ }
+ fmt.Printf("\n");
+}
+
+/* Find smallest and largest solutions */
+func smallest_largest() (smallest, largest *[50]int8) {
+ smallest = &solutions[0];
+ largest = &solutions[0];
+ for i := 1; i < solution_count; i++ {
+ candidate := &solutions[i];
+ for j, s := range *smallest {
+ c := candidate[j];
+ if c == s {
+ continue
+ }
+ if c < s {
+ smallest = candidate;
+ }
+ break;
+ }
+ for j, s := range *largest {
+ c := candidate[j];
+ if c == s {
+ continue
+ }
+ if c > s {
+ largest = candidate;
+ }
+ break;
+ }
+ }
+ return;
+}
+
+func main() {
+ flag.Parse();
+ calc_pieces();
+ calc_rows();
+ solve(0, 0);
+ fmt.Printf("%d solutions found\n\n", solution_count);
+ smallest, largest := smallest_largest();
+ pretty(smallest);
+ pretty(largest);
+}
--- /dev/null
+2098 solutions found
+
+0 0 0 0 1
+ 2 2 2 0 1
+2 6 6 1 1
+ 2 6 1 5 5
+8 6 5 5 5
+ 8 6 3 3 3
+4 8 8 9 3
+ 4 4 8 9 3
+4 7 4 7 9
+ 7 7 7 9 9
+
+9 9 9 9 8
+ 9 6 6 8 5
+6 6 8 8 5
+ 6 8 2 5 5
+7 7 7 2 5
+ 7 4 7 2 0
+1 4 2 2 0
+ 1 4 4 0 3
+1 4 0 0 3
+ 1 1 3 3 3
+
gccgo -O2 mandelbrot.go 57.49u 0.01s 57.51r
gc mandelbrot 74.32u 0.00s 74.35r
gc_B mandelbrot 74.28u 0.01s 74.31r
+
+meteor 16000
+ gcc -O2 meteor-contest.c 0.10u 0.00s 0.10r
+ gccgo -O2 meteor-contest.go 0.12u 0.00s 0.14r
+ gc meteor-contest 0.24u 0.00s 0.26r
+ gc_B meteor-contest 0.23u 0.00s 0.24r
run 'gc_B mandelbrot' $O.out -n 16000
}
+meteor() {
+ echo 'meteor 16000'
+ run 'gcc -O2 meteor-contest.c' a.out
+ run 'gccgo -O2 meteor-contest.go' a.out
+ run 'gc meteor-contest' $O.out
+ run 'gc_B meteor-contest' $O.out
+}
+
case $# in
0)
- run="fasta revcom nbody binarytree fannkuch regexdna spectralnorm knucleotide mandelbrot"
+ run="fasta revcom nbody binarytree fannkuch regexdna spectralnorm knucleotide mandelbrot meteor"
;;
*)
run=$*