A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
Certainly! Here's a plan for the program to count the total number of unholy 8x8 matrices: 1. Define constants and types: - Define a constant for the matrix size (8x8) - Use unsigned long long to represent the matrix (64 bits) 2. Implement the is_unholy function: - Take an unsigned long long as input - Use bit shifting and masking to check for isolated 1s - Return 1 if unholy, 0 otherwise 3. Implement the dynamic programming solution: - Create a recursive function count_unholy_matrices - Parameters: current row, previous two rows - Base case: when all 8 rows are processed, return 1 if unholy - Recursive case: - Enumerate all 2^16 possibilities for the next two rows - For each possibility, check if it's compatible with the previous rows - If compatible, recursively call the function for the next row - Sum up all the valid possibilities 4. Implement the main function: - Call count_unholy_matrices with initial parameters - Print the result Now, let's implement this plan in C:
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 32 33 34 35 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_rows) { if (row == ROWS) { return is_unholy(prev_rows); } uint64_t count = 0; for (uint32_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t current = ((uint64_t)prev_rows << 16) | next_rows; if (row >= 2 && !is_unholy(current & 0xFFFFFFFF)) { continue; } count += count_unholy_matrices(row + 2, next_rows); } return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
I extracted the following code from that output:
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 32 33 34 35 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_rows) { if (row == ROWS) { return is_unholy(prev_rows); } uint64_t count = 0; for (uint32_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t current = ((uint64_t)prev_rows << 16) | next_rows; if (row >= 2 && !is_unholy(current & 0xFFFFFFFF)) { continue; } count += count_unholy_matrices(row + 2, next_rows); } return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
Running the following program:
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 32 33 34 35 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_rows) { if (row == ROWS) { return is_unholy(prev_rows); } uint64_t count = 0; for (uint32_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t current = ((uint64_t)prev_rows << 16) | next_rows; if (row >= 2 && !is_unholy(current & 0xFFFFFFFF)) { continue; } count += count_unholy_matrices(row + 2, next_rows); } return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
Timeout: function took too long to complete
Testing if the previous output contains the string 1121231537486377866
: False
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
Here's a plan for the program to count the number of unholy 8x8 matrices: 1. Define constants and data structures: - Define the matrix size (8x8) - Define a type for the matrix representation (unsigned long long) - Define a structure to store memoized results 2. Implement the is_unholy function: - Take a matrix as input (unsigned long long) - Use bit shifting and masking to check for isolated 1s - Return true if the matrix is unholy, false otherwise 3. Implement the count_unholy_matrices function: - Use dynamic programming with memoization - Base case: when all rows are filled - Recursive case: try all possibilities for the next two rows - Use bitwise operations to efficiently check and update the matrix 4. Implement the main function: - Initialize the memoization structure - Call count_unholy_matrices with initial empty matrix - Print the result Now, let's implement this plan in C:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MEMO_SIZE (1 << 16) typedef unsigned long long matrix_t; struct MemoEntry { int row; unsigned short prev_rows; unsigned long long count; }; struct MemoEntry memo[MEMO_SIZE]; bool is_unholy(matrix_t matrix) { matrix_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } unsigned long long count_unholy_matrices(int row, unsigned short prev_rows, matrix_t current) { if (row == ROWS) { return is_unholy(current) ? 1 : 0; } int memo_index = (row << 16) | prev_rows; if (memo[memo_index].row == row && memo[memo_index].prev_rows == prev_rows) { return memo[memo_index].count; } unsigned long long count = 0; unsigned int next_two_rows_max = (row == 6) ? (1 << 8) : (1 << 16); for (unsigned int next_two_rows = 0; next_two_rows < next_two_rows_max; next_two_rows++) { matrix_t new_matrix = current | ((matrix_t)next_two_rows << (row * 8)); if (is_unholy(new_matrix)) { count += count_unholy_matrices(row + 2, next_two_rows & 0xFFFF, new_matrix); } } memo[memo_index].row = row; memo[memo_index].prev_rows = prev_rows; memo[memo_index].count = count; return count; } int main() { memset(memo, 0, sizeof(memo)); unsigned long long result = count_unholy_matrices(0, 0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
I extracted the following code from that output:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MEMO_SIZE (1 << 16) typedef unsigned long long matrix_t; struct MemoEntry { int row; unsigned short prev_rows; unsigned long long count; }; struct MemoEntry memo[MEMO_SIZE]; bool is_unholy(matrix_t matrix) { matrix_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } unsigned long long count_unholy_matrices(int row, unsigned short prev_rows, matrix_t current) { if (row == ROWS) { return is_unholy(current) ? 1 : 0; } int memo_index = (row << 16) | prev_rows; if (memo[memo_index].row == row && memo[memo_index].prev_rows == prev_rows) { return memo[memo_index].count; } unsigned long long count = 0; unsigned int next_two_rows_max = (row == 6) ? (1 << 8) : (1 << 16); for (unsigned int next_two_rows = 0; next_two_rows < next_two_rows_max; next_two_rows++) { matrix_t new_matrix = current | ((matrix_t)next_two_rows << (row * 8)); if (is_unholy(new_matrix)) { count += count_unholy_matrices(row + 2, next_two_rows & 0xFFFF, new_matrix); } } memo[memo_index].row = row; memo[memo_index].prev_rows = prev_rows; memo[memo_index].count = count; return count; } int main() { memset(memo, 0, sizeof(memo)); unsigned long long result = count_unholy_matrices(0, 0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
Running the following program:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MEMO_SIZE (1 << 16) typedef unsigned long long matrix_t; struct MemoEntry { int row; unsigned short prev_rows; unsigned long long count; }; struct MemoEntry memo[MEMO_SIZE]; bool is_unholy(matrix_t matrix) { matrix_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); return isolated == 0; } unsigned long long count_unholy_matrices(int row, unsigned short prev_rows, matrix_t current) { if (row == ROWS) { return is_unholy(current) ? 1 : 0; } int memo_index = (row << 16) | prev_rows; if (memo[memo_index].row == row && memo[memo_index].prev_rows == prev_rows) { return memo[memo_index].count; } unsigned long long count = 0; unsigned int next_two_rows_max = (row == 6) ? (1 << 8) : (1 << 16); for (unsigned int next_two_rows = 0; next_two_rows < next_two_rows_max; next_two_rows++) { matrix_t new_matrix = current | ((matrix_t)next_two_rows << (row * 8)); if (is_unholy(new_matrix)) { count += count_unholy_matrices(row + 2, next_two_rows & 0xFFFF, new_matrix); } } memo[memo_index].row = row; memo[memo_index].prev_rows = prev_rows; memo[memo_index].count = count; return count; } int main() { memset(memo, 0, sizeof(memo)); unsigned long long result = count_unholy_matrices(0, 0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
Total number of unholy 8x8 matrices: 0
Testing if the previous output contains the string 1121231537486377866
: False
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
Certainly! Let's break this down into a plan and then implement it in C. Plan: 1. Define constants and data structures: - Matrix size (8x8) - Unsigned long to represent the matrix (64 bits) 2. Implement the is_unholy function: - Take an unsigned long as input - Use bit shifting and masking to check for isolated 1s - Return 1 if unholy, 0 otherwise 3. Implement the dynamic programming solution: - Create a recursive function count_unholy_matrices - Base case: when all 8 rows are filled - Recursive case: - Enumerate all 2^16 possibilities for the next two rows - Check if the new configuration is compatible with the previous rows - If compatible, recurse with the new configuration 4. Main function: - Call count_unholy_matrices with initial empty matrix - Print the result Now, let's implement this plan in C:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t above = matrix >> MATRIX_SIZE; uint64_t below = matrix << MATRIX_SIZE; uint64_t left = (matrix & ~ROW_MASK) << 1; uint64_t right = (matrix & ~(ROW_MASK << (MATRIX_SIZE - 1))) >> 1; return (matrix & ~(above | below | left | right)) == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(uint64_t current_matrix, int rows_filled) { if (rows_filled == MATRIX_SIZE) { return is_unholy(current_matrix); } uint64_t count = 0; uint16_t new_rows; for (new_rows = 0; new_rows < (1 << 16); new_rows++) { uint64_t new_matrix = (current_matrix << 16) | new_rows; if (rows_filled >= 2) { uint64_t check_matrix = new_matrix & (0xFFFFFFFFFFFF0000ULL >> (48 - rows_filled * 8)); if (!is_unholy(check_matrix)) { continue; } } count += count_unholy_matrices(new_matrix, rows_filled + 2); } return count; } int main() { uint64_t total_unholy = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy); return 0; } |
I extracted the following code from that output:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t above = matrix >> MATRIX_SIZE; uint64_t below = matrix << MATRIX_SIZE; uint64_t left = (matrix & ~ROW_MASK) << 1; uint64_t right = (matrix & ~(ROW_MASK << (MATRIX_SIZE - 1))) >> 1; return (matrix & ~(above | below | left | right)) == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(uint64_t current_matrix, int rows_filled) { if (rows_filled == MATRIX_SIZE) { return is_unholy(current_matrix); } uint64_t count = 0; uint16_t new_rows; for (new_rows = 0; new_rows < (1 << 16); new_rows++) { uint64_t new_matrix = (current_matrix << 16) | new_rows; if (rows_filled >= 2) { uint64_t check_matrix = new_matrix & (0xFFFFFFFFFFFF0000ULL >> (48 - rows_filled * 8)); if (!is_unholy(check_matrix)) { continue; } } count += count_unholy_matrices(new_matrix, rows_filled + 2); } return count; } int main() { uint64_t total_unholy = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy); return 0; } |
Running the following program:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t above = matrix >> MATRIX_SIZE; uint64_t below = matrix << MATRIX_SIZE; uint64_t left = (matrix & ~ROW_MASK) << 1; uint64_t right = (matrix & ~(ROW_MASK << (MATRIX_SIZE - 1))) >> 1; return (matrix & ~(above | below | left | right)) == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(uint64_t current_matrix, int rows_filled) { if (rows_filled == MATRIX_SIZE) { return is_unholy(current_matrix); } uint64_t count = 0; uint16_t new_rows; for (new_rows = 0; new_rows < (1 << 16); new_rows++) { uint64_t new_matrix = (current_matrix << 16) | new_rows; if (rows_filled >= 2) { uint64_t check_matrix = new_matrix & (0xFFFFFFFFFFFF0000ULL >> (48 - rows_filled * 8)); if (!is_unholy(check_matrix)) { continue; } } count += count_unholy_matrices(new_matrix, rows_filled + 2); } return count; } int main() { uint64_t total_unholy = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy); return 0; } |
Timeout: function took too long to complete
Testing if the previous output contains the string 1121231537486377866
: False
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
Certainly! Here's a plan for the program, followed by its implementation in C: Plan: 1. Define constants for matrix size and bit operations. 2. Implement the is_unholy function using bit operations to check for isolated 1s. 3. Create a dynamic programming function that: a. Uses recursion based on the number of rows. b. Enumerates all possible combinations for the next two rows. c. Checks if the current configuration is valid using is_unholy. d. Accumulates the count of unholy matrices. 4. In the main function, call the dynamic programming function and print the result. Here's the C implementation based on this plan:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 #define MASK_ROW 0xFFFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << COLS) | (matrix >> COLS)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_two_rows) { static uint64_t memo[ROWS/2][1 << 16] = {0}; if (row == ROWS) { return 1; } if (memo[row/2][prev_two_rows] != 0) { return memo[row/2][prev_two_rows]; } uint64_t count = 0; uint32_t next_two_rows; for (next_two_rows = 0; next_two_rows <= MASK_ROW; next_two_rows++) { uint64_t matrix = ((uint64_t)prev_two_rows << 32) | ((uint64_t)next_two_rows << 16); if (is_unholy(matrix)) { count += count_unholy_matrices(row + 2, next_two_rows); } } memo[row/2][prev_two_rows] = count; return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
I extracted the following code from that output:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 #define MASK_ROW 0xFFFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << COLS) | (matrix >> COLS)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_two_rows) { static uint64_t memo[ROWS/2][1 << 16] = {0}; if (row == ROWS) { return 1; } if (memo[row/2][prev_two_rows] != 0) { return memo[row/2][prev_two_rows]; } uint64_t count = 0; uint32_t next_two_rows; for (next_two_rows = 0; next_two_rows <= MASK_ROW; next_two_rows++) { uint64_t matrix = ((uint64_t)prev_two_rows << 32) | ((uint64_t)next_two_rows << 16); if (is_unholy(matrix)) { count += count_unholy_matrices(row + 2, next_two_rows); } } memo[row/2][prev_two_rows] = count; return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
Running the following program:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 | #include <stdio.h> #include <stdint.h> #define ROWS 8 #define COLS 8 #define MASK_ROW 0xFFFF // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { uint64_t isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << COLS) | (matrix >> COLS)); return isolated == 0; } // Dynamic programming function to count unholy matrices uint64_t count_unholy_matrices(int row, uint32_t prev_two_rows) { static uint64_t memo[ROWS/2][1 << 16] = {0}; if (row == ROWS) { return 1; } if (memo[row/2][prev_two_rows] != 0) { return memo[row/2][prev_two_rows]; } uint64_t count = 0; uint32_t next_two_rows; for (next_two_rows = 0; next_two_rows <= MASK_ROW; next_two_rows++) { uint64_t matrix = ((uint64_t)prev_two_rows << 32) | ((uint64_t)next_two_rows << 16); if (is_unholy(matrix)) { count += count_unholy_matrices(row + 2, next_two_rows); } } memo[row/2][prev_two_rows] = count; return count; } int main() { uint64_t total = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", total); return 0; } |
Timeout: function took too long to complete
Testing if the previous output contains the string 1121231537486377866
: False
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
A binary 8x8 matrix is 'unholy' if there are no isolated 1s. A 1 is isolated if there isn't another 1 in any of the 4 direct cardinal directions. Write a C program that counts the total number of unholy 8x8 matricies.To solve this question: - Use bit arithmetic and an unsigned long to represent the matrix. - Write a function is_unholy that tests if a matrix is unholy by bit-shifting and masking. Use a dynamic program to count the number of unholy matricies. - Recurse on the number of rows the matrix has. - Enumerate all 2^16 next two rows. This is enough to completely isolate the prior solutions from the next. Write out a plan for the program, and then implement the plan in C.
Here's a plan for the program to count the number of unholy 8x8 matrices: 1. Define constants and data structures: - Define matrix size (8x8) - Use unsigned long long to represent the matrix (64 bits) - Create a structure to hold memoization data 2. Implement the is_unholy function: - Take an unsigned long long as input - Use bit shifting and masking to check for isolated 1s - Return true if no isolated 1s are found, false otherwise 3. Implement the dynamic programming function: - Take parameters: current row, previous two rows, memoization array - Base case: if current row is 8, return 1 if matrix is unholy, 0 otherwise - Check memoization array for existing result - Enumerate all 2^16 possibilities for the next two rows - Recursively call the function for each valid combination - Sum up the results and store in memoization array - Return the total count 4. Implement the main function: - Initialize memoization array - Call the dynamic programming function with initial parameters - Print the result Now, let's implement this plan in C:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MAX_STATES (1 << 16) typedef unsigned long long ull; struct MemoState { int row; ull prev_rows; ull count; }; struct MemoState memo[ROWS][MAX_STATES]; bool is_unholy(ull matrix) { ull mask = 0x8080808080808080ULL; for (int i = 0; i < COLS; i++) { ull isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); if (isolated & mask) return false; mask >>= 1; } return true; } ull count_unholy(int row, ull prev_rows) { if (row == ROWS) { return is_unholy(prev_rows) ? 1 : 0; } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == row && memo[row][i].prev_rows == prev_rows) { return memo[row][i].count; } } ull total = 0; ull mask = (1ULL << 16) - 1; for (ull next_rows = 0; next_rows < (1ULL << 16); next_rows++) { ull new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { total += count_unholy(row + 2, next_rows); } } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == 0) { memo[row][i].row = row; memo[row][i].prev_rows = prev_rows; memo[row][i].count = total; break; } } return total; } int main() { memset(memo, 0, sizeof(memo)); ull result = count_unholy(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
I extracted the following code from that output:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MAX_STATES (1 << 16) typedef unsigned long long ull; struct MemoState { int row; ull prev_rows; ull count; }; struct MemoState memo[ROWS][MAX_STATES]; bool is_unholy(ull matrix) { ull mask = 0x8080808080808080ULL; for (int i = 0; i < COLS; i++) { ull isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); if (isolated & mask) return false; mask >>= 1; } return true; } ull count_unholy(int row, ull prev_rows) { if (row == ROWS) { return is_unholy(prev_rows) ? 1 : 0; } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == row && memo[row][i].prev_rows == prev_rows) { return memo[row][i].count; } } ull total = 0; ull mask = (1ULL << 16) - 1; for (ull next_rows = 0; next_rows < (1ULL << 16); next_rows++) { ull new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { total += count_unholy(row + 2, next_rows); } } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == 0) { memo[row][i].row = row; memo[row][i].prev_rows = prev_rows; memo[row][i].count = total; break; } } return total; } int main() { memset(memo, 0, sizeof(memo)); ull result = count_unholy(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
Running the following program:
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 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define ROWS 8 #define COLS 8 #define MAX_STATES (1 << 16) typedef unsigned long long ull; struct MemoState { int row; ull prev_rows; ull count; }; struct MemoState memo[ROWS][MAX_STATES]; bool is_unholy(ull matrix) { ull mask = 0x8080808080808080ULL; for (int i = 0; i < COLS; i++) { ull isolated = matrix & ~((matrix << 1) | (matrix >> 1) | (matrix << 8) | (matrix >> 8)); if (isolated & mask) return false; mask >>= 1; } return true; } ull count_unholy(int row, ull prev_rows) { if (row == ROWS) { return is_unholy(prev_rows) ? 1 : 0; } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == row && memo[row][i].prev_rows == prev_rows) { return memo[row][i].count; } } ull total = 0; ull mask = (1ULL << 16) - 1; for (ull next_rows = 0; next_rows < (1ULL << 16); next_rows++) { ull new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { total += count_unholy(row + 2, next_rows); } } for (int i = 0; i < MAX_STATES; i++) { if (memo[row][i].row == 0) { memo[row][i].row = row; memo[row][i].prev_rows = prev_rows; memo[row][i].count = total; break; } } return total; } int main() { memset(memo, 0, sizeof(memo)); ull result = count_unholy(0, 0); printf("Total number of unholy 8x8 matrices: %llu\n", result); return 0; } |
Total number of unholy 8x8 matrices: 0
Testing if the previous output contains the string 1121231537486377866
: False