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.
## Plan for the program: 1. **Data Representation:** * Use an `unsigned long` to represent an 8x8 matrix. Each bit in the `unsigned long` corresponds to a cell in the matrix, with the least significant bit representing the bottom-left cell and the most significant bit representing the top-right cell. 2. **Function `is_unholy`:** * This function takes an `unsigned long` representing the matrix as input. * It iterates over each cell in the matrix, checking if it is a 1. * For each 1, it checks the four neighboring cells using bit-shifting and masking. * If any of the neighboring cells are also 1s, the matrix is not unholy and the function returns 0. * If all neighboring cells are 0s, the matrix is unholy and the function returns 1. 3. **Dynamic Programming:** * Define a function `count_unholy_matrices(int rows)` that takes the number of remaining rows as input. * If `rows == 0`, return 1 (base case: an empty matrix is unholy). * Otherwise, iterate over all possible combinations of the next two rows (2^16 possibilities). * For each combination, call `is_unholy` on the combined matrix. * If the matrix is unholy, recursively call `count_unholy_matrices(rows - 2)` to count the number of unholy matrices for the remaining rows. * Return the sum of the results for all combinations. ## C code implementation:
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 | #include <stdio.h> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { int cell = row * 8 + col; // Check if the cell is a 1 if ((matrix >> cell) & 1) { // Check neighboring cells for (int i = -1; i <= 1; i++) { for (int j = -1; j <= 1; j++) { int neighbor_row = row + i; int neighbor_col = col + j; // Check if neighbor is within bounds and a 1 if (neighbor_row >= 0 && neighbor_row < 8 && neighbor_col >= 0 && neighbor_col < 8 && ((matrix >> (neighbor_row * 8 + neighbor_col)) & 1)) { return 0; // Not unholy } } } } } } return 1; // Unholy } // Function to count the number of unholy matrices unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long combined_matrix = (next_rows << 16) | (next_rows << 8); if (is_unholy(combined_matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int rows = 8; unsigned long total_unholy_matrices = count_unholy_matrices(rows); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); 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 | #include <stdio.h> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { int cell = row * 8 + col; // Check if the cell is a 1 if ((matrix >> cell) & 1) { // Check neighboring cells for (int i = -1; i <= 1; i++) { for (int j = -1; j <= 1; j++) { int neighbor_row = row + i; int neighbor_col = col + j; // Check if neighbor is within bounds and a 1 if (neighbor_row >= 0 && neighbor_row < 8 && neighbor_col >= 0 && neighbor_col < 8 && ((matrix >> (neighbor_row * 8 + neighbor_col)) & 1)) { return 0; // Not unholy } } } } } } return 1; // Unholy } // Function to count the number of unholy matrices unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long combined_matrix = (next_rows << 16) | (next_rows << 8); if (is_unholy(combined_matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int rows = 8; unsigned long total_unholy_matrices = count_unholy_matrices(rows); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); 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 | #include <stdio.h> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { int cell = row * 8 + col; // Check if the cell is a 1 if ((matrix >> cell) & 1) { // Check neighboring cells for (int i = -1; i <= 1; i++) { for (int j = -1; j <= 1; j++) { int neighbor_row = row + i; int neighbor_col = col + j; // Check if neighbor is within bounds and a 1 if (neighbor_row >= 0 && neighbor_row < 8 && neighbor_col >= 0 && neighbor_col < 8 && ((matrix >> (neighbor_row * 8 + neighbor_col)) & 1)) { return 0; // Not unholy } } } } } } return 1; // Unholy } // Function to count the number of unholy matrices unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long combined_matrix = (next_rows << 16) | (next_rows << 8); if (is_unholy(combined_matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int rows = 8; unsigned long total_unholy_matrices = count_unholy_matrices(rows); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); return 0; } |
Total number of unholy 8x8 matrices: 1
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.
## Plan 1. **Define an `is_unholy` function:** - This function takes an `unsigned long` representing the matrix and checks if it's unholy. - It uses bit-shifting and masking to check for isolated 1s in each row. - Return 1 if unholy, 0 otherwise. 2. **Implement a dynamic programming solution:** - Define a function `count_unholy_matrices(int rows_remaining)`. - Base case: If `rows_remaining` is 0, return 1 (one valid empty matrix). - Recursive case: - Iterate through all possible combinations of the next two rows (2^16 possibilities). - For each combination, check if the resulting matrix is unholy using `is_unholy`. - If unholy, recursively call `count_unholy_matrices` with `rows_remaining - 2` and add the result to the total count. - Return the total count. 3. **Main function:** - Call `count_unholy_matrices(8)` to get the total count of unholy 8x8 matrices. - Print the result. ## C Implementation
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 | #include <stdio.h> // Check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { // Check each bit in the row for (int col = 0; col < 8; col++) { int bit = 1 << (row * 8 + col); // Check if the bit is set and all neighbors are 0 if ((matrix & bit) && !(matrix & (bit << 1)) && !(matrix & (bit >> 1)) && !(matrix & (bit << 8)) && !(matrix & (bit >> 8))) { return 1; // Unholy } } } return 0; // Holy } // Count unholy matrices using dynamic programming int count_unholy_matrices(int rows_remaining) { if (rows_remaining == 0) { return 1; } int count = 0; // Iterate through all possible combinations of the next two rows for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { // Check if the resulting matrix is unholy if (is_unholy((next_rows << 16) | next_rows)) { count += count_unholy_matrices(rows_remaining - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total unholy 8x8 matrices: %d\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 | #include <stdio.h> // Check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { // Check each bit in the row for (int col = 0; col < 8; col++) { int bit = 1 << (row * 8 + col); // Check if the bit is set and all neighbors are 0 if ((matrix & bit) && !(matrix & (bit << 1)) && !(matrix & (bit >> 1)) && !(matrix & (bit << 8)) && !(matrix & (bit >> 8))) { return 1; // Unholy } } } return 0; // Holy } // Count unholy matrices using dynamic programming int count_unholy_matrices(int rows_remaining) { if (rows_remaining == 0) { return 1; } int count = 0; // Iterate through all possible combinations of the next two rows for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { // Check if the resulting matrix is unholy if (is_unholy((next_rows << 16) | next_rows)) { count += count_unholy_matrices(rows_remaining - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total unholy 8x8 matrices: %d\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 | #include <stdio.h> // Check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { // Check each bit in the row for (int col = 0; col < 8; col++) { int bit = 1 << (row * 8 + col); // Check if the bit is set and all neighbors are 0 if ((matrix & bit) && !(matrix & (bit << 1)) && !(matrix & (bit >> 1)) && !(matrix & (bit << 8)) && !(matrix & (bit >> 8))) { return 1; // Unholy } } } return 0; // Holy } // Count unholy matrices using dynamic programming int count_unholy_matrices(int rows_remaining) { if (rows_remaining == 0) { return 1; } int count = 0; // Iterate through all possible combinations of the next two rows for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { // Check if the resulting matrix is unholy if (is_unholy((next_rows << 16) | next_rows)) { count += count_unholy_matrices(rows_remaining - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total unholy 8x8 matrices: %d\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.
## Plan: 1. **Define the matrix representation:** - Use an `unsigned long` to represent the 8x8 matrix. - Each bit in the `unsigned long` corresponds to a cell in the matrix, with the least significant bit representing the bottom-left cell and the most significant bit representing the top-right cell. 2. **Define the `is_unholy` function:** - This function takes an `unsigned long` representing the matrix as input. - It iterates over each cell in the matrix, checking if the cell is a 1 and if it is isolated. - A cell is isolated if all its four direct cardinal neighbors (up, down, left, right) are 0s. - The function uses bit-shifting and masking operations to efficiently check the neighbors of each cell. - It returns 1 if the matrix is unholy, and 0 otherwise. 3. **Implement the dynamic programming solution:** - Define a function `count_unholy_matrices(int rows)` that recursively calculates the number of unholy matrices with the given number of rows. - The base case is when `rows` is 0, in which case there is only 1 possible matrix (all 0s), so return 1. - For each possible value of the next two rows (2^16 possibilities), call `is_unholy` to check if the resulting matrix is unholy. - If the matrix is unholy, add 1 to the count. - Recursively call `count_unholy_matrices` with `rows - 2` to count the remaining rows. - Return the total count of unholy matrices. ## C Implementation:
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> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { // Check if the current cell is a 1 and isolated if ((matrix >> (row * 8 + col)) & 1) { // Check neighbors if (((matrix >> (row * 8 + col + 1)) & 1) || ((matrix >> (row * 8 + col - 1)) & 1) || ((matrix >> ((row + 1) * 8 + col)) & 1) || ((matrix >> ((row - 1) * 8 + col)) & 1)) { // Not isolated, not unholy return 0; } } } } return 1; } // Function to count unholy matrices using dynamic programming unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; // Enumerate all possible values for the next two rows for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long matrix = (next_rows << 16) | (rows > 2 ? (next_rows >> 16) : 0); if (is_unholy(matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total number of unholy 8x8 matrices: %d\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 | #include <stdio.h> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { // Check if the current cell is a 1 and isolated if ((matrix >> (row * 8 + col)) & 1) { // Check neighbors if (((matrix >> (row * 8 + col + 1)) & 1) || ((matrix >> (row * 8 + col - 1)) & 1) || ((matrix >> ((row + 1) * 8 + col)) & 1) || ((matrix >> ((row - 1) * 8 + col)) & 1)) { // Not isolated, not unholy return 0; } } } } return 1; } // Function to count unholy matrices using dynamic programming unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; // Enumerate all possible values for the next two rows for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long matrix = (next_rows << 16) | (rows > 2 ? (next_rows >> 16) : 0); if (is_unholy(matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total number of unholy 8x8 matrices: %d\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 | #include <stdio.h> // Function to check if a matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { // Check if the current cell is a 1 and isolated if ((matrix >> (row * 8 + col)) & 1) { // Check neighbors if (((matrix >> (row * 8 + col + 1)) & 1) || ((matrix >> (row * 8 + col - 1)) & 1) || ((matrix >> ((row + 1) * 8 + col)) & 1) || ((matrix >> ((row - 1) * 8 + col)) & 1)) { // Not isolated, not unholy return 0; } } } } return 1; } // Function to count unholy matrices using dynamic programming unsigned long count_unholy_matrices(int rows) { if (rows == 0) { return 1; } unsigned long count = 0; // Enumerate all possible values for the next two rows for (unsigned long next_rows = 0; next_rows < (1 << 16); next_rows++) { // Combine current rows with next two rows unsigned long matrix = (next_rows << 16) | (rows > 2 ? (next_rows >> 16) : 0); if (is_unholy(matrix)) { count += count_unholy_matrices(rows - 2); } } return count; } int main() { int total_unholy = count_unholy_matrices(8); printf("Total number of unholy 8x8 matrices: %d\n", total_unholy); return 0; } |
Timeout: function took too long to complete
Testing if the previous output contains the string 1121231537486377866
: False