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.
Given the complexity of the task, let's first outline a plan and then dive into the implementation: ### Plan 1. **Representation of the Matrix:** - Since the matrix is 8x8 and binary, we can use an `unsigned long` to represent it, where each bit represents a cell in the matrix. The first 8 bits are the first row, the next 8 bits are the second row, and so on. 2. **Checking if a Matrix is Unholy:** - To check if a 1 is isolated, we need to check its immediate neighbors in the north, south, east, and west directions. This can be done using bit-shifting and masking operations. 3. **Dynamic Programming Approach:** - We will use a recursive function that counts the number of unholy matrices by progressively considering more rows. The base case is when we have considered all 8 rows. - To avoid recalculating for the same configurations of the already processed rows, we will store the intermediate results in a cache. 4. **Enumerating the Next Two Rows:** - For each recursion step, we need to consider all possible combinations of the next two rows (2^16 possibilities) and check if adding them keeps the matrix unholy. ### 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 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define CACHE_SIZE (1 << (2*MAX_ROWS)) // 2^16 unsigned long cache[CACHE_SIZE]; // Checks if a given matrix is unholy. bool is_unholy(unsigned long matrix) { for (int row = 0; row < MAX_ROWS; row++) { for (int col = 0; col < MAX_ROWS; col++) { int bit_position = row * MAX_ROWS + col; if (matrix & (1UL << bit_position)) { // If current position is 1 bool isolated = true; // Check North if (row > 0 && (matrix & (1UL << (bit_position - MAX_ROWS)))) isolated = false; // Check South if (row < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + MAX_ROWS)))) isolated = false; // Check East if (col < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + 1)))) isolated = false; // Check West if (col > 0 && (matrix & (1UL << (bit_position - 1)))) isolated = false; if (isolated) return false; // Found an isolated 1 } } } return true; // No isolated 1s } // Dynamic programming function to count unholy matrices. unsigned long count_unholy(unsigned long matrix, int rows) { if (rows == MAX_ROWS) { if (is_unholy(matrix)) return 1; else return 0; } // Check if result is already cached. if (cache[matrix] != -1) { return cache[matrix]; } unsigned long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (2*MAX_ROWS)); next_rows++) { unsigned long new_matrix = matrix | ((unsigned long)next_rows << (rows * MAX_ROWS)); count += count_unholy(new_matrix, rows + 2); } // Cache the result before returning. cache[matrix] = count; return count; } int main() { memset(cache, -1, sizeof(cache)); // Initialize cache with -1. unsigned long total = count_unholy(0, 0); printf("Total unholy matrices: %lu\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 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define CACHE_SIZE (1 << (2*MAX_ROWS)) // 2^16 unsigned long cache[CACHE_SIZE]; // Checks if a given matrix is unholy. bool is_unholy(unsigned long matrix) { for (int row = 0; row < MAX_ROWS; row++) { for (int col = 0; col < MAX_ROWS; col++) { int bit_position = row * MAX_ROWS + col; if (matrix & (1UL << bit_position)) { // If current position is 1 bool isolated = true; // Check North if (row > 0 && (matrix & (1UL << (bit_position - MAX_ROWS)))) isolated = false; // Check South if (row < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + MAX_ROWS)))) isolated = false; // Check East if (col < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + 1)))) isolated = false; // Check West if (col > 0 && (matrix & (1UL << (bit_position - 1)))) isolated = false; if (isolated) return false; // Found an isolated 1 } } } return true; // No isolated 1s } // Dynamic programming function to count unholy matrices. unsigned long count_unholy(unsigned long matrix, int rows) { if (rows == MAX_ROWS) { if (is_unholy(matrix)) return 1; else return 0; } // Check if result is already cached. if (cache[matrix] != -1) { return cache[matrix]; } unsigned long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (2*MAX_ROWS)); next_rows++) { unsigned long new_matrix = matrix | ((unsigned long)next_rows << (rows * MAX_ROWS)); count += count_unholy(new_matrix, rows + 2); } // Cache the result before returning. cache[matrix] = count; return count; } int main() { memset(cache, -1, sizeof(cache)); // Initialize cache with -1. unsigned long total = count_unholy(0, 0); printf("Total unholy matrices: %lu\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 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define CACHE_SIZE (1 << (2*MAX_ROWS)) // 2^16 unsigned long cache[CACHE_SIZE]; // Checks if a given matrix is unholy. bool is_unholy(unsigned long matrix) { for (int row = 0; row < MAX_ROWS; row++) { for (int col = 0; col < MAX_ROWS; col++) { int bit_position = row * MAX_ROWS + col; if (matrix & (1UL << bit_position)) { // If current position is 1 bool isolated = true; // Check North if (row > 0 && (matrix & (1UL << (bit_position - MAX_ROWS)))) isolated = false; // Check South if (row < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + MAX_ROWS)))) isolated = false; // Check East if (col < MAX_ROWS - 1 && (matrix & (1UL << (bit_position + 1)))) isolated = false; // Check West if (col > 0 && (matrix & (1UL << (bit_position - 1)))) isolated = false; if (isolated) return false; // Found an isolated 1 } } } return true; // No isolated 1s } // Dynamic programming function to count unholy matrices. unsigned long count_unholy(unsigned long matrix, int rows) { if (rows == MAX_ROWS) { if (is_unholy(matrix)) return 1; else return 0; } // Check if result is already cached. if (cache[matrix] != -1) { return cache[matrix]; } unsigned long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (2*MAX_ROWS)); next_rows++) { unsigned long new_matrix = matrix | ((unsigned long)next_rows << (rows * MAX_ROWS)); count += count_unholy(new_matrix, rows + 2); } // Cache the result before returning. cache[matrix] = count; return count; } int main() { memset(cache, -1, sizeof(cache)); // Initialize cache with -1. unsigned long total = count_unholy(0, 0); printf("Total unholy matrices: %lu\n", total); return 0; } |
main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out
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.
To tackle this problem, let's break it down into steps following the guidelines provided: ### Plan 1. **Representation of the Matrix**: - Use an `unsigned long` to represent the 8x8 matrix, as each bit can represent a cell in the matrix, allowing for efficient bitwise operations. 2. **Function to Check if a Matrix is Unholy**: - Implement `is_unholy` function that takes an `unsigned long` representing the matrix and returns `1` if the matrix is unholy, and `0` otherwise. - Use bit shifting and masking to check adjacent cells for each 1 in the matrix. 3. **Dynamic Programming Approach**: - Use recursion to count the total number of unholy matrices, based on the number of rows processed. - For each step, enumerate all possible configurations for the next two rows (2^16 possibilities) and check if adding these rows keeps the matrix unholy. - Cache intermediate results to avoid recalculating for the same partial matrix configurations. 4. **Main Algorithm**: - Start with an empty matrix and recursively fill it row by row, checking for the unholy condition as we go. - Keep a global counter to accumulate the total number of unholy matrices found. ### 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 51 52 53 54 55 56 57 58 59 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 64 #define ROW_MASK 0xFF // Mask for a single row (8 bits set) unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo); // Checks if the current matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix >> i) & 1) { // If there's a 1 at position i // Check cardinal directions (exclude edges) if (!((i % 8 == 0 || (matrix >> (i - 1)) & 1) && // Left (i % 8 == 7 || (matrix >> (i + 1)) & 1) && // Right (i < 8 || (matrix >> (i - 8)) & 1) && // Up (i >= 56 || (matrix >> (i + 8)) & 1))) { // Down return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo) { if (rows == 8) { // Base case: all rows filled return is_unholy(current_matrix); } // Check if result is already memoized if (memo[(rows << 16) | current_matrix] != -1) { return memo[(rows << 16) | current_matrix]; } unsigned long long total = 0; // Enumerate all possibilities for the next row (2^8) for (unsigned int next_row = 0; next_row <= 0xFF; next_row++) { unsigned long new_matrix = (current_matrix << 8) | next_row; // Add next row to current matrix total += count_unholy_matrices(rows + 1, new_matrix, memo); // Recurse } // Memoize and return result memo[(rows << 16) | current_matrix] = total; return total; } int main() { unsigned long long memo[8 * (1 << 16)]; memset(memo, -1, sizeof(memo)); // Initialize memo array with -1 unsigned long long total_unholy_matrices = count_unholy_matrices(0, 0, memo); printf("Total Unholy Matrices: %llu\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 51 52 53 54 55 56 57 58 59 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 64 #define ROW_MASK 0xFF // Mask for a single row (8 bits set) unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo); // Checks if the current matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix >> i) & 1) { // If there's a 1 at position i // Check cardinal directions (exclude edges) if (!((i % 8 == 0 || (matrix >> (i - 1)) & 1) && // Left (i % 8 == 7 || (matrix >> (i + 1)) & 1) && // Right (i < 8 || (matrix >> (i - 8)) & 1) && // Up (i >= 56 || (matrix >> (i + 8)) & 1))) { // Down return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo) { if (rows == 8) { // Base case: all rows filled return is_unholy(current_matrix); } // Check if result is already memoized if (memo[(rows << 16) | current_matrix] != -1) { return memo[(rows << 16) | current_matrix]; } unsigned long long total = 0; // Enumerate all possibilities for the next row (2^8) for (unsigned int next_row = 0; next_row <= 0xFF; next_row++) { unsigned long new_matrix = (current_matrix << 8) | next_row; // Add next row to current matrix total += count_unholy_matrices(rows + 1, new_matrix, memo); // Recurse } // Memoize and return result memo[(rows << 16) | current_matrix] = total; return total; } int main() { unsigned long long memo[8 * (1 << 16)]; memset(memo, -1, sizeof(memo)); // Initialize memo array with -1 unsigned long long total_unholy_matrices = count_unholy_matrices(0, 0, memo); printf("Total Unholy Matrices: %llu\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 51 52 53 54 55 56 57 58 59 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 64 #define ROW_MASK 0xFF // Mask for a single row (8 bits set) unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo); // Checks if the current matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix >> i) & 1) { // If there's a 1 at position i // Check cardinal directions (exclude edges) if (!((i % 8 == 0 || (matrix >> (i - 1)) & 1) && // Left (i % 8 == 7 || (matrix >> (i + 1)) & 1) && // Right (i < 8 || (matrix >> (i - 8)) & 1) && // Up (i >= 56 || (matrix >> (i + 8)) & 1))) { // Down return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy_matrices(int rows, unsigned long current_matrix, unsigned long long *memo) { if (rows == 8) { // Base case: all rows filled return is_unholy(current_matrix); } // Check if result is already memoized if (memo[(rows << 16) | current_matrix] != -1) { return memo[(rows << 16) | current_matrix]; } unsigned long long total = 0; // Enumerate all possibilities for the next row (2^8) for (unsigned int next_row = 0; next_row <= 0xFF; next_row++) { unsigned long new_matrix = (current_matrix << 8) | next_row; // Add next row to current matrix total += count_unholy_matrices(rows + 1, new_matrix, memo); // Recurse } // Memoize and return result memo[(rows << 16) | current_matrix] = total; return total; } int main() { unsigned long long memo[8 * (1 << 16)]; memset(memo, -1, sizeof(memo)); // Initialize memo array with -1 unsigned long long total_unholy_matrices = count_unholy_matrices(0, 0, memo); printf("Total Unholy Matrices: %llu\n", total_unholy_matrices); return 0; } |
main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out
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.
Given the complexity and constraints of this problem, I'll start by outlining a plan for the program and then proceed to implement it according to the plan. ### Plan for the Program 1. **Represent the Matrix:** - Use an `unsigned long` to represent the 8x8 matrix, where each bit corresponds to a cell in the matrix. 2. **Function `is_unholy`:** - Write a function `is_unholy` that accepts an `unsigned long` representing the matrix and returns if the matrix is unholy. Use bit-shifting and masking to identify isolated 1s. 3. **Dynamic Programming Approach:** - Use dynamic programming to count the number of unholy matrices. The state of the DP will be defined by how many rows have been processed so far. 4. **Enumerate Next Two Rows:** - For each state, enumerate all possible configurations of the next two rows (2^16 possibilities) and check if they lead to an unholy matrix when combined with the state representing the already processed rows. 5. **Recursion with Memoization:** - Implement recursion with memoization to avoid recalculating the count for states that have already been processed. 6. **Main Logic:** - The main function will initialize the dynamic programming and start the recursion from the state representing 0 processed rows. It will output the total count of unholy matrices. ### C Program 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 51 52 53 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define MAX_STATES (1 << 16) // 2^16 possible states for two rows // Memoization array unsigned long long dp[MAX_ROWS + 1][MAX_STATES]; // Checks if the given matrix configuration is unholy bool is_unholy(unsigned long matrix) { for (int i = 0; i < 64; i++) { // Check all bits if (matrix & (1ULL << i)) { // If bit is 1 // Check if isolated if (!((i % 8 > 0 && (matrix & (1ULL << (i - 1)))) || // Left (i % 8 < 7 && (matrix & (1ULL << (i + 1)))) || // Right (i > 7 && (matrix & (1ULL << (i - 8)))) || // Up (i < 56 && (matrix & (1ULL << (i + 8))))) // Down ) { return false; // Found an isolated 1 } } } return true; // No isolated 1s, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int processedRows, unsigned long prevRows) { if (processedRows == MAX_ROWS) return is_unholy(prevRows); // Check memoization if(dp[processedRows][prevRows] != -1) return dp[processedRows][prevRows]; unsigned long long count = 0; for (int i = 0; i < MAX_STATES; i++) { // Enumerate next two rows unsigned long nextRows = (prevRows << 16) | i; // Combine with previous state if (is_unholy(nextRows)) { count += count_unholy(processedRows + 2, nextRows >> (8 * (processedRows >= 6 ? 2 : 0))); } } dp[processedRows][prevRows] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize memoization array unsigned long long totalCount = count_unholy(0, 0); // Start recursion printf("Total number of unholy 8x8 matrices: %llu\n", totalCount); 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 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define MAX_STATES (1 << 16) // 2^16 possible states for two rows // Memoization array unsigned long long dp[MAX_ROWS + 1][MAX_STATES]; // Checks if the given matrix configuration is unholy bool is_unholy(unsigned long matrix) { for (int i = 0; i < 64; i++) { // Check all bits if (matrix & (1ULL << i)) { // If bit is 1 // Check if isolated if (!((i % 8 > 0 && (matrix & (1ULL << (i - 1)))) || // Left (i % 8 < 7 && (matrix & (1ULL << (i + 1)))) || // Right (i > 7 && (matrix & (1ULL << (i - 8)))) || // Up (i < 56 && (matrix & (1ULL << (i + 8))))) // Down ) { return false; // Found an isolated 1 } } } return true; // No isolated 1s, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int processedRows, unsigned long prevRows) { if (processedRows == MAX_ROWS) return is_unholy(prevRows); // Check memoization if(dp[processedRows][prevRows] != -1) return dp[processedRows][prevRows]; unsigned long long count = 0; for (int i = 0; i < MAX_STATES; i++) { // Enumerate next two rows unsigned long nextRows = (prevRows << 16) | i; // Combine with previous state if (is_unholy(nextRows)) { count += count_unholy(processedRows + 2, nextRows >> (8 * (processedRows >= 6 ? 2 : 0))); } } dp[processedRows][prevRows] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize memoization array unsigned long long totalCount = count_unholy(0, 0); // Start recursion printf("Total number of unholy 8x8 matrices: %llu\n", totalCount); 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 | #include <stdio.h> #include <stdbool.h> #include <string.h> #define MAX_ROWS 8 #define MAX_STATES (1 << 16) // 2^16 possible states for two rows // Memoization array unsigned long long dp[MAX_ROWS + 1][MAX_STATES]; // Checks if the given matrix configuration is unholy bool is_unholy(unsigned long matrix) { for (int i = 0; i < 64; i++) { // Check all bits if (matrix & (1ULL << i)) { // If bit is 1 // Check if isolated if (!((i % 8 > 0 && (matrix & (1ULL << (i - 1)))) || // Left (i % 8 < 7 && (matrix & (1ULL << (i + 1)))) || // Right (i > 7 && (matrix & (1ULL << (i - 8)))) || // Up (i < 56 && (matrix & (1ULL << (i + 8))))) // Down ) { return false; // Found an isolated 1 } } } return true; // No isolated 1s, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int processedRows, unsigned long prevRows) { if (processedRows == MAX_ROWS) return is_unholy(prevRows); // Check memoization if(dp[processedRows][prevRows] != -1) return dp[processedRows][prevRows]; unsigned long long count = 0; for (int i = 0; i < MAX_STATES; i++) { // Enumerate next two rows unsigned long nextRows = (prevRows << 16) | i; // Combine with previous state if (is_unholy(nextRows)) { count += count_unholy(processedRows + 2, nextRows >> (8 * (processedRows >= 6 ? 2 : 0))); } } dp[processedRows][prevRows] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize memoization array unsigned long long totalCount = count_unholy(0, 0); // Start recursion printf("Total number of unholy 8x8 matrices: %llu\n", totalCount); 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.
To tackle this problem, we'll break it down into several steps as outlined in the plan below, and then proceed to implement it in C. ### Plan 1. **Representation**: Use an `unsigned long` to represent an 8x8 binary matrix, where each bit represents a cell in the matrix. 2. **is_unholy Function**: Implement a function to check if a given matrix is unholy. This involves checking each 1 bit to see if it has another 1 bit in any of the 4 cardinal directions. 3. **Dynamic Programming Approach**: Use dynamic programming to count the number of unholy matrices, considering one or two rows at a time and building up to the full 8x8 matrix. 4. **Recursion with Memoization**: Implement recursion to explore all possible matrices row by row, using memoization to avoid recalculating the number of unholy matrices for any given partial configuration. 5. **Bit Arithmetic for Next Rows**: For each partial matrix, enumerate all 2^16 possible configurations of the next two rows, ensuring these do not make the matrix holy (i.e., ensure that no 1s become isolated). ### 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 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Mask for one row #define FULL_MASK 0xFFFFFFFFFFFFFFFF // Mask for the full 8x8 matrix unsigned long long dp[1 << 16]; // DP array for memoization, large enough for all 2-row states // Check if a given matrix (up to row) is unholy int is_unholy(unsigned long matrix, int rows) { for (int row = 0; row < rows; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { // If this is a 1, check for neighbors if ((matrix >> (row * MATRIX_SIZE + col)) & 1) { int hasNeighbor = 0; // Check above if (row > 0 && (matrix >> ((row - 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check below if (row < rows - 1 && (matrix >> ((row + 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check left if (col > 0 && (matrix >> (row * MATRIX_SIZE + col - 1)) & 1) hasNeighbor = 1; // Check right if (col < MATRIX_SIZE - 1 && (matrix >> (row * MATRIX_SIZE + col + 1)) & 1) hasNeighbor = 1; if (!hasNeighbor) return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found } // Recursive function to count unholy matrices, given a partial matrix represented by 'state' unsigned long long count_unholy(unsigned long state, int rows) { // Base case: if we've filled all rows and the matrix is unholy if (rows == MATRIX_SIZE) { return is_unholy(state, rows); } // Check memoization if (dp[state] != -1) return dp[state]; unsigned long long count = 0; // Try all possible next rows for (unsigned int nextRow = 0; nextRow < (1 << MATRIX_SIZE); nextRow++) { unsigned long newState = (state << MATRIX_SIZE) | nextRow; count += count_unholy(newState, rows + 1); } // Memoize and return the result dp[state] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize DP array with -1 unsigned long long total_unholy = count_unholy(0, 0); // Start with an empty matrix printf("Total number of unholy 8x8 matrices: %llu\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 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Mask for one row #define FULL_MASK 0xFFFFFFFFFFFFFFFF // Mask for the full 8x8 matrix unsigned long long dp[1 << 16]; // DP array for memoization, large enough for all 2-row states // Check if a given matrix (up to row) is unholy int is_unholy(unsigned long matrix, int rows) { for (int row = 0; row < rows; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { // If this is a 1, check for neighbors if ((matrix >> (row * MATRIX_SIZE + col)) & 1) { int hasNeighbor = 0; // Check above if (row > 0 && (matrix >> ((row - 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check below if (row < rows - 1 && (matrix >> ((row + 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check left if (col > 0 && (matrix >> (row * MATRIX_SIZE + col - 1)) & 1) hasNeighbor = 1; // Check right if (col < MATRIX_SIZE - 1 && (matrix >> (row * MATRIX_SIZE + col + 1)) & 1) hasNeighbor = 1; if (!hasNeighbor) return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found } // Recursive function to count unholy matrices, given a partial matrix represented by 'state' unsigned long long count_unholy(unsigned long state, int rows) { // Base case: if we've filled all rows and the matrix is unholy if (rows == MATRIX_SIZE) { return is_unholy(state, rows); } // Check memoization if (dp[state] != -1) return dp[state]; unsigned long long count = 0; // Try all possible next rows for (unsigned int nextRow = 0; nextRow < (1 << MATRIX_SIZE); nextRow++) { unsigned long newState = (state << MATRIX_SIZE) | nextRow; count += count_unholy(newState, rows + 1); } // Memoize and return the result dp[state] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize DP array with -1 unsigned long long total_unholy = count_unholy(0, 0); // Start with an empty matrix printf("Total number of unholy 8x8 matrices: %llu\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 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | #include <stdio.h> #include <stdlib.h> #include <string.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Mask for one row #define FULL_MASK 0xFFFFFFFFFFFFFFFF // Mask for the full 8x8 matrix unsigned long long dp[1 << 16]; // DP array for memoization, large enough for all 2-row states // Check if a given matrix (up to row) is unholy int is_unholy(unsigned long matrix, int rows) { for (int row = 0; row < rows; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { // If this is a 1, check for neighbors if ((matrix >> (row * MATRIX_SIZE + col)) & 1) { int hasNeighbor = 0; // Check above if (row > 0 && (matrix >> ((row - 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check below if (row < rows - 1 && (matrix >> ((row + 1) * MATRIX_SIZE + col)) & 1) hasNeighbor = 1; // Check left if (col > 0 && (matrix >> (row * MATRIX_SIZE + col - 1)) & 1) hasNeighbor = 1; // Check right if (col < MATRIX_SIZE - 1 && (matrix >> (row * MATRIX_SIZE + col + 1)) & 1) hasNeighbor = 1; if (!hasNeighbor) return 0; // Found an isolated 1 } } } return 1; // No isolated 1s found } // Recursive function to count unholy matrices, given a partial matrix represented by 'state' unsigned long long count_unholy(unsigned long state, int rows) { // Base case: if we've filled all rows and the matrix is unholy if (rows == MATRIX_SIZE) { return is_unholy(state, rows); } // Check memoization if (dp[state] != -1) return dp[state]; unsigned long long count = 0; // Try all possible next rows for (unsigned int nextRow = 0; nextRow < (1 << MATRIX_SIZE); nextRow++) { unsigned long newState = (state << MATRIX_SIZE) | nextRow; count += count_unholy(newState, rows + 1); } // Memoize and return the result dp[state] = count; return count; } int main() { memset(dp, -1, sizeof(dp)); // Initialize DP array with -1 unsigned long long total_unholy = count_unholy(0, 0); // Start with an empty matrix printf("Total number of unholy 8x8 matrices: %llu\n", total_unholy); return 0; } |
Total number of unholy 8x8 matrices: 146680
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.
To tackle this problem, we'll first outline a plan based on the requirements and constraints you've provided, and then we will implement it in C. ### Plan 1. **Matrix Representation**: - Use an `unsigned long` (assuming it's 64-bit) to represent the 8x8 matrix, where each bit corresponds to a cell in the matrix. 2. **is_unholy Function**: - This function will take an `unsigned long` representing the matrix and determine if it is "unholy" by checking that each `1` bit is not isolated. - It will use bit-shifting and masking to inspect the neighbors of each bit. 3. **Dynamic Programming Approach**: - Use a recursive function that takes the number of rows processed so far and the current state of the matrix as arguments. - At each step, enumerate all possible configurations for the next two rows (2^16 possibilities) and check if they can be added without violating the "unholy" property. - Use memoization to avoid recomputing states. 4. **Base Case and Recursion**: - The base case occurs when all 8 rows have been processed. If we reach this point, we have found a valid "unholy" matrix, so we return 1. - Otherwise, for each recursive call, enumerate all possible states for the next two rows, and keep a running total of the counts of "unholy" matrices. 5. **Main Function**: - Initialize the dynamic programming array or use a hash table for memoization. - Call the recursive function with 0 rows processed initially and an empty matrix. - Print the final count of "unholy" matrices. ### Implementation Let's now translate this plan into C code.
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 <stdint.h> // Assuming 64-bit unsigned long #define MATRIX_SIZE 64 #define ROWS 8 #define COLS 8 // Use a simple hash map for memoization (for demonstration purposes; a real implementation may need a more efficient approach) unsigned long long dp[1 << (ROWS * 2)]; // Enough space for a simple demonstration int dp_filled[1 << (ROWS * 2)] = {0}; // To check if a dp value has been filled // Function to check if a matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < ROWS; row++) { for (int col = 0; col < COLS; col++) { int bit_pos = row * COLS + col; unsigned long bit = (matrix >> bit_pos) & 1UL; if (bit == 1) { // If current bit is 1, check for isolation unsigned long neighbors = 0; if (row > 0) neighbors |= (matrix >> ((row-1) * COLS + col)) & 1UL; // Up if (row < ROWS-1) neighbors |= (matrix >> ((row+1) * COLS + col)) & 1UL; // Down if (col > 0) neighbors |= (matrix >> (row * COLS + (col-1))) & 1UL; // Left if (col < COLS-1) neighbors |= (matrix >> (row * COLS + (col+1))) & 1UL; // Right if (neighbors == 0) return 0; // Isolated 1 found } } } return 1; // Not isolated, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int rows_processed, unsigned long matrix) { if (rows_processed == ROWS) return is_unholy(matrix); int idx = (rows_processed << 16) | (matrix & ((1UL << 16) - 1)); // Simple hash if (dp_filled[idx]) return dp[idx]; unsigned long long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (COLS * 2)); next_rows++) { unsigned long new_matrix = (matrix << (COLS * 2)) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows_processed + 2, new_matrix); } } dp[idx] = count; dp_filled[idx] = 1; return count; } int main() { unsigned long long total_unholy = count_unholy(0, 0UL); printf("Total Unholy Matrices: %llu\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 47 48 49 50 51 52 53 54 55 56 | #include <stdio.h> #include <stdint.h> // Assuming 64-bit unsigned long #define MATRIX_SIZE 64 #define ROWS 8 #define COLS 8 // Use a simple hash map for memoization (for demonstration purposes; a real implementation may need a more efficient approach) unsigned long long dp[1 << (ROWS * 2)]; // Enough space for a simple demonstration int dp_filled[1 << (ROWS * 2)] = {0}; // To check if a dp value has been filled // Function to check if a matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < ROWS; row++) { for (int col = 0; col < COLS; col++) { int bit_pos = row * COLS + col; unsigned long bit = (matrix >> bit_pos) & 1UL; if (bit == 1) { // If current bit is 1, check for isolation unsigned long neighbors = 0; if (row > 0) neighbors |= (matrix >> ((row-1) * COLS + col)) & 1UL; // Up if (row < ROWS-1) neighbors |= (matrix >> ((row+1) * COLS + col)) & 1UL; // Down if (col > 0) neighbors |= (matrix >> (row * COLS + (col-1))) & 1UL; // Left if (col < COLS-1) neighbors |= (matrix >> (row * COLS + (col+1))) & 1UL; // Right if (neighbors == 0) return 0; // Isolated 1 found } } } return 1; // Not isolated, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int rows_processed, unsigned long matrix) { if (rows_processed == ROWS) return is_unholy(matrix); int idx = (rows_processed << 16) | (matrix & ((1UL << 16) - 1)); // Simple hash if (dp_filled[idx]) return dp[idx]; unsigned long long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (COLS * 2)); next_rows++) { unsigned long new_matrix = (matrix << (COLS * 2)) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows_processed + 2, new_matrix); } } dp[idx] = count; dp_filled[idx] = 1; return count; } int main() { unsigned long long total_unholy = count_unholy(0, 0UL); printf("Total Unholy Matrices: %llu\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 47 48 49 50 51 52 53 54 55 56 | #include <stdio.h> #include <stdint.h> // Assuming 64-bit unsigned long #define MATRIX_SIZE 64 #define ROWS 8 #define COLS 8 // Use a simple hash map for memoization (for demonstration purposes; a real implementation may need a more efficient approach) unsigned long long dp[1 << (ROWS * 2)]; // Enough space for a simple demonstration int dp_filled[1 << (ROWS * 2)] = {0}; // To check if a dp value has been filled // Function to check if a matrix configuration is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < ROWS; row++) { for (int col = 0; col < COLS; col++) { int bit_pos = row * COLS + col; unsigned long bit = (matrix >> bit_pos) & 1UL; if (bit == 1) { // If current bit is 1, check for isolation unsigned long neighbors = 0; if (row > 0) neighbors |= (matrix >> ((row-1) * COLS + col)) & 1UL; // Up if (row < ROWS-1) neighbors |= (matrix >> ((row+1) * COLS + col)) & 1UL; // Down if (col > 0) neighbors |= (matrix >> (row * COLS + (col-1))) & 1UL; // Left if (col < COLS-1) neighbors |= (matrix >> (row * COLS + (col+1))) & 1UL; // Right if (neighbors == 0) return 0; // Isolated 1 found } } } return 1; // Not isolated, matrix is unholy } // Recursive function to count unholy matrices unsigned long long count_unholy(int rows_processed, unsigned long matrix) { if (rows_processed == ROWS) return is_unholy(matrix); int idx = (rows_processed << 16) | (matrix & ((1UL << 16) - 1)); // Simple hash if (dp_filled[idx]) return dp[idx]; unsigned long long count = 0; for (unsigned int next_rows = 0; next_rows < (1 << (COLS * 2)); next_rows++) { unsigned long new_matrix = (matrix << (COLS * 2)) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows_processed + 2, new_matrix); } } dp[idx] = count; dp_filled[idx] = 1; return count; } int main() { unsigned long long total_unholy = count_unholy(0, 0UL); printf("Total Unholy Matrices: %llu\n", total_unholy); return 0; } |
main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out
Testing if the previous output contains the string 1121231537486377866
: False