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 down the plan for the program step by step and then implement it in C. ### Plan 1. **Matrix Representation**: - Use an `unsigned long` to represent the matrix. Each bit of the `unsigned long` will represent a cell in the 8x8 matrix. - The 8x8 matrix has 64 cells, so we need 64 bits. Since an `unsigned long` typically has at least 64 bits, it’s suitable for this purpose. 2. **Function to Check if Matrix is Unholy**: - Implement a function `is_unholy` that takes an `unsigned long` matrix and returns whether it is unholy. - Use bit-shifting and masking to check all the neighbors of each 1 in the matrix. 3. **Dynamic Programming Approach**: - Use dynamic programming to count the number of unholy matrices. - Recurse on the number of rows the matrix has. - Enumerate all possible configurations for the next two rows (2^16 possibilities) and check if they form an unholy matrix when combined with the already verified rows. ### Implementation 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 67 68 69 70 71 72 73 74 75 76 77 78 79 | #include <stdio.h> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 #define TOTAL_ROWS 8 // Function prototypes bool is_unholy(unsigned long matrix); unsigned long mask_8x8(int row, int col); unsigned long shift_left(unsigned long matrix); unsigned long shift_right(unsigned long matrix); unsigned long shift_up(unsigned long matrix); unsigned long shift_down(unsigned long matrix); unsigned long count_unholy_matrices(int row, unsigned long prev_row); int main() { unsigned long total_unholy_matrices = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); return 0; } bool is_unholy(unsigned long matrix) { unsigned long left = shift_left(matrix); unsigned long right = shift_right(matrix); unsigned long up = shift_up(matrix); unsigned long down = shift_down(matrix); unsigned long neighbor_mask = left | right | up | down; // Check if there are any isolated 1s if ((matrix & ~neighbor_mask) != 0) { return false; } return true; } unsigned long mask_8x8(int row, int col) { return 1UL << (row * ROW_SIZE + col); } unsigned long shift_left(unsigned long matrix) { return (matrix & 0xFEFEFEFEFEFEFEFEUL) << 1; } unsigned long shift_right(unsigned long matrix) { return (matrix & 0x7F7F7F7F7F7F7F7FUL) >> 1; } unsigned long shift_up(unsigned long matrix) { return matrix << ROW_SIZE; } unsigned long shift_down(unsigned long matrix) { return matrix >> ROW_SIZE; } unsigned long count_unholy_matrices(int row, unsigned long prev_row) { if (row == TOTAL_ROWS) { // Base case: we have processed all rows return 1; } unsigned long count = 0; // Enumerate all possible configurations for the next two rows (2^16 possibilities) for (unsigned long next_row = 0; next_row < (1UL << ROW_SIZE); next_row++) { // Combine previous rows with the new row unsigned long combined = (prev_row << ROW_SIZE) | next_row; if (is_unholy(combined)) { // Recur for the next row count += count_unholy_matrices(row + 1, next_row); } } return count; } |
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 67 68 69 70 71 72 73 74 75 76 77 78 79 | #include <stdio.h> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 #define TOTAL_ROWS 8 // Function prototypes bool is_unholy(unsigned long matrix); unsigned long mask_8x8(int row, int col); unsigned long shift_left(unsigned long matrix); unsigned long shift_right(unsigned long matrix); unsigned long shift_up(unsigned long matrix); unsigned long shift_down(unsigned long matrix); unsigned long count_unholy_matrices(int row, unsigned long prev_row); int main() { unsigned long total_unholy_matrices = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); return 0; } bool is_unholy(unsigned long matrix) { unsigned long left = shift_left(matrix); unsigned long right = shift_right(matrix); unsigned long up = shift_up(matrix); unsigned long down = shift_down(matrix); unsigned long neighbor_mask = left | right | up | down; // Check if there are any isolated 1s if ((matrix & ~neighbor_mask) != 0) { return false; } return true; } unsigned long mask_8x8(int row, int col) { return 1UL << (row * ROW_SIZE + col); } unsigned long shift_left(unsigned long matrix) { return (matrix & 0xFEFEFEFEFEFEFEFEUL) << 1; } unsigned long shift_right(unsigned long matrix) { return (matrix & 0x7F7F7F7F7F7F7F7FUL) >> 1; } unsigned long shift_up(unsigned long matrix) { return matrix << ROW_SIZE; } unsigned long shift_down(unsigned long matrix) { return matrix >> ROW_SIZE; } unsigned long count_unholy_matrices(int row, unsigned long prev_row) { if (row == TOTAL_ROWS) { // Base case: we have processed all rows return 1; } unsigned long count = 0; // Enumerate all possible configurations for the next two rows (2^16 possibilities) for (unsigned long next_row = 0; next_row < (1UL << ROW_SIZE); next_row++) { // Combine previous rows with the new row unsigned long combined = (prev_row << ROW_SIZE) | next_row; if (is_unholy(combined)) { // Recur for the next row count += count_unholy_matrices(row + 1, next_row); } } return count; } |
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 67 68 69 70 71 72 73 74 75 76 77 78 79 | #include <stdio.h> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 #define TOTAL_ROWS 8 // Function prototypes bool is_unholy(unsigned long matrix); unsigned long mask_8x8(int row, int col); unsigned long shift_left(unsigned long matrix); unsigned long shift_right(unsigned long matrix); unsigned long shift_up(unsigned long matrix); unsigned long shift_down(unsigned long matrix); unsigned long count_unholy_matrices(int row, unsigned long prev_row); int main() { unsigned long total_unholy_matrices = count_unholy_matrices(0, 0); printf("Total number of unholy 8x8 matrices: %lu\n", total_unholy_matrices); return 0; } bool is_unholy(unsigned long matrix) { unsigned long left = shift_left(matrix); unsigned long right = shift_right(matrix); unsigned long up = shift_up(matrix); unsigned long down = shift_down(matrix); unsigned long neighbor_mask = left | right | up | down; // Check if there are any isolated 1s if ((matrix & ~neighbor_mask) != 0) { return false; } return true; } unsigned long mask_8x8(int row, int col) { return 1UL << (row * ROW_SIZE + col); } unsigned long shift_left(unsigned long matrix) { return (matrix & 0xFEFEFEFEFEFEFEFEUL) << 1; } unsigned long shift_right(unsigned long matrix) { return (matrix & 0x7F7F7F7F7F7F7F7FUL) >> 1; } unsigned long shift_up(unsigned long matrix) { return matrix << ROW_SIZE; } unsigned long shift_down(unsigned long matrix) { return matrix >> ROW_SIZE; } unsigned long count_unholy_matrices(int row, unsigned long prev_row) { if (row == TOTAL_ROWS) { // Base case: we have processed all rows return 1; } unsigned long count = 0; // Enumerate all possible configurations for the next two rows (2^16 possibilities) for (unsigned long next_row = 0; next_row < (1UL << ROW_SIZE); next_row++) { // Combine previous rows with the new row unsigned long combined = (prev_row << ROW_SIZE) | next_row; if (is_unholy(combined)) { // Recur for the next row count += count_unholy_matrices(row + 1, next_row); } } return count; } |
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 Problem and Data Structures**: - Use an `unsigned long` to represent the 8x8 binary matrix. - Create a function `is_unholy` to check if a matrix is unholy. - Use dynamic programming to count the number of unholy matrices. 2. **`is_unholy` Function**: - Check each 1 in the matrix to see if it has another 1 in any of the 4 cardinal directions (up, down, left, right). - Use bit-shifting and masking to perform these checks efficiently. 3. **Dynamic Programming Setup**: - Use recursion to build the matrix row by row. - Enumerate all possible states for the next two rows (2^16 combinations). - Use memoization to store results for subproblems. 4. **Implement the Program**: - Write the `is_unholy` function. - Write the dynamic programming function to count unholy matrices. - Combine these components in a main function to compute and print the result. ### 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 62 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if the given 8x8 matrix is unholy int is_unholy(uint64_t matrix) { int i, j; for (i = 0; i < MATRIX_SIZE; i++) { for (j = 0; j < MATRIX_SIZE; j++) { uint64_t bit = 1ULL << (i * MATRIX_SIZE + j); if (matrix & bit) { int has_neighbor = 0; if (i > 0 && (matrix & (bit >> MATRIX_SIZE))) has_neighbor = 1; // check up if (i < MATRIX_SIZE - 1 && (matrix & (bit << MATRIX_SIZE))) has_neighbor = 1; // check down if (j > 0 && (matrix & (bit >> 1))) has_neighbor = 1; // check left if (j < MATRIX_SIZE - 1 && (matrix & (bit << 1))) has_neighbor = 1; // check right if (!has_neighbor) return 0; // isolated 1 found } } } return 1; // no isolated 1s } // Function to count the number of unholy matrices uint64_t count_unholy(int rows, uint64_t prev_row_mask, uint64_t next_row_mask, uint64_t memo[256][256][MATRIX_SIZE + 1]) { if (rows == MATRIX_SIZE) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE); return is_unholy(matrix) ? 1 : 0; } if (memo[prev_row_mask][next_row_mask][rows] != (uint64_t)-1) { return memo[prev_row_mask][next_row_mask][rows]; } uint64_t count = 0; for (uint64_t new_row_mask = 0; new_row_mask < (1 << MATRIX_SIZE); new_row_mask++) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE) | (new_row_mask << (2 * MATRIX_SIZE)); if (is_unholy(matrix)) { count += count_unholy(rows + 1, next_row_mask, new_row_mask, memo); } } memo[prev_row_mask][next_row_mask][rows] = count; return count; } int main() { uint64_t memo[256][256][MATRIX_SIZE + 1]; for (int i = 0; i < 256; i++) { for (int j = 0; j < 256; j++) { for (int k = 0; k <= MATRIX_SIZE; k++) { memo[i][j][k] = (uint64_t)-1; } } } uint64_t total_unholy_matrices = count_unholy(1, 0, 0, memo); printf("Total number of unholy 8x8 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 60 61 62 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if the given 8x8 matrix is unholy int is_unholy(uint64_t matrix) { int i, j; for (i = 0; i < MATRIX_SIZE; i++) { for (j = 0; j < MATRIX_SIZE; j++) { uint64_t bit = 1ULL << (i * MATRIX_SIZE + j); if (matrix & bit) { int has_neighbor = 0; if (i > 0 && (matrix & (bit >> MATRIX_SIZE))) has_neighbor = 1; // check up if (i < MATRIX_SIZE - 1 && (matrix & (bit << MATRIX_SIZE))) has_neighbor = 1; // check down if (j > 0 && (matrix & (bit >> 1))) has_neighbor = 1; // check left if (j < MATRIX_SIZE - 1 && (matrix & (bit << 1))) has_neighbor = 1; // check right if (!has_neighbor) return 0; // isolated 1 found } } } return 1; // no isolated 1s } // Function to count the number of unholy matrices uint64_t count_unholy(int rows, uint64_t prev_row_mask, uint64_t next_row_mask, uint64_t memo[256][256][MATRIX_SIZE + 1]) { if (rows == MATRIX_SIZE) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE); return is_unholy(matrix) ? 1 : 0; } if (memo[prev_row_mask][next_row_mask][rows] != (uint64_t)-1) { return memo[prev_row_mask][next_row_mask][rows]; } uint64_t count = 0; for (uint64_t new_row_mask = 0; new_row_mask < (1 << MATRIX_SIZE); new_row_mask++) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE) | (new_row_mask << (2 * MATRIX_SIZE)); if (is_unholy(matrix)) { count += count_unholy(rows + 1, next_row_mask, new_row_mask, memo); } } memo[prev_row_mask][next_row_mask][rows] = count; return count; } int main() { uint64_t memo[256][256][MATRIX_SIZE + 1]; for (int i = 0; i < 256; i++) { for (int j = 0; j < 256; j++) { for (int k = 0; k <= MATRIX_SIZE; k++) { memo[i][j][k] = (uint64_t)-1; } } } uint64_t total_unholy_matrices = count_unholy(1, 0, 0, memo); printf("Total number of unholy 8x8 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 60 61 62 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define ROW_MASK 0xFF // Function to check if the given 8x8 matrix is unholy int is_unholy(uint64_t matrix) { int i, j; for (i = 0; i < MATRIX_SIZE; i++) { for (j = 0; j < MATRIX_SIZE; j++) { uint64_t bit = 1ULL << (i * MATRIX_SIZE + j); if (matrix & bit) { int has_neighbor = 0; if (i > 0 && (matrix & (bit >> MATRIX_SIZE))) has_neighbor = 1; // check up if (i < MATRIX_SIZE - 1 && (matrix & (bit << MATRIX_SIZE))) has_neighbor = 1; // check down if (j > 0 && (matrix & (bit >> 1))) has_neighbor = 1; // check left if (j < MATRIX_SIZE - 1 && (matrix & (bit << 1))) has_neighbor = 1; // check right if (!has_neighbor) return 0; // isolated 1 found } } } return 1; // no isolated 1s } // Function to count the number of unholy matrices uint64_t count_unholy(int rows, uint64_t prev_row_mask, uint64_t next_row_mask, uint64_t memo[256][256][MATRIX_SIZE + 1]) { if (rows == MATRIX_SIZE) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE); return is_unholy(matrix) ? 1 : 0; } if (memo[prev_row_mask][next_row_mask][rows] != (uint64_t)-1) { return memo[prev_row_mask][next_row_mask][rows]; } uint64_t count = 0; for (uint64_t new_row_mask = 0; new_row_mask < (1 << MATRIX_SIZE); new_row_mask++) { uint64_t matrix = prev_row_mask | (next_row_mask << MATRIX_SIZE) | (new_row_mask << (2 * MATRIX_SIZE)); if (is_unholy(matrix)) { count += count_unholy(rows + 1, next_row_mask, new_row_mask, memo); } } memo[prev_row_mask][next_row_mask][rows] = count; return count; } int main() { uint64_t memo[256][256][MATRIX_SIZE + 1]; for (int i = 0; i < 256; i++) { for (int j = 0; j < 256; j++) { for (int k = 0; k <= MATRIX_SIZE; k++) { memo[i][j][k] = (uint64_t)-1; } } } uint64_t total_unholy_matrices = count_unholy(1, 0, 0, memo); printf("Total number of unholy 8x8 matrices: %llu\n", total_unholy_matrices); return 0; } |
Total number of unholy 8x8 matrices: 115224736374666
main.c: In function 'main':
main.c:61:53: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 2 has type 'uint64_t' {aka 'long unsigned int'} [-Wformat=]
61 | printf("Total number of unholy 8x8 matrices: %llu\n", total_unholy_matrices);
| ~~~^ ~~~~~~~~~~~~~~~~~~~~~
| | |
| | uint64_t {aka long unsigned int}
| long long unsigned int
| %lu
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.
Sure, let's start by outlining a plan for the program: ### Plan 1. **Representation of the Matrix:** - Use an `unsigned long long` to represent the 8x8 binary matrix. This provides 64 bits, enough to represent each element in the 8x8 matrix. 2. **Function to Check if a Matrix is Unholy:** - Implement a function `int is_unholy(unsigned long long matrix)` that checks if a matrix is unholy. This function will: - Iterate through each bit in the matrix. - For each bit that is 1, check its neighboring bits (up, down, left, right). - Return 0 if any 1 is isolated, otherwise return 1. 3. **Recursive Dynamic Programming Approach:** - Use a dynamic programming approach to count the number of unholy matrices. - Use recursion to handle the number of rows in the matrix. - Enumerate all possible configurations of the next two rows (2^16 possibilities). - Use a memoization technique to store already computed results for certain row configurations to avoid redundant computations. ### Implementation Here is the implementation of the 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 67 68 69 70 71 72 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define TOTAL_BITS (MATRIX_SIZE * MATRIX_SIZE) // Function to check if a bit at (row, col) is isolated int is_isolated(uint64_t matrix, int row, int col) { int bit_pos = row * MATRIX_SIZE + col; uint64_t mask = 1ULL << bit_pos; // If the bit is 0, it's not isolated if ((matrix & mask) == 0) { return 0; } // Check adjacent bits (up, down, left, right) if (row > 0 && (matrix & (mask >> MATRIX_SIZE))) return 0; // Up if (row < MATRIX_SIZE - 1 && (matrix & (mask << MATRIX_SIZE))) return 0; // Down if (col > 0 && (matrix & (mask >> 1))) return 0; // Left if (col < MATRIX_SIZE - 1 && (matrix & (mask << 1))) return 0; // Right // If none of the adjacent bits are 1, it's isolated return 1; } // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { for (int row = 0; row < MATRIX_SIZE; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { if (is_isolated(matrix, row, col)) { return 0; } } } return 1; } // Dynamic programming function to count unholy matrices uint64_t count_unholy(int rows, uint64_t prev_rows, uint64_t dp[][1 << 16]) { if (rows == MATRIX_SIZE) { return is_unholy(prev_rows); } if (dp[rows][prev_rows] != -1) { return dp[rows][prev_rows]; } uint64_t count = 0; for (uint64_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows + 2, next_rows, dp); } } return dp[rows][prev_rows] = count; } int main() { uint64_t dp[MATRIX_SIZE][1 << 16]; for (int i = 0; i < MATRIX_SIZE; i++) { for (int j = 0; j < (1 << 16); j++) { dp[i][j] = -1; } } uint64_t count = count_unholy(0, 0, dp); printf("Total number of unholy matrices: %llu\n", count); 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 67 68 69 70 71 72 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define TOTAL_BITS (MATRIX_SIZE * MATRIX_SIZE) // Function to check if a bit at (row, col) is isolated int is_isolated(uint64_t matrix, int row, int col) { int bit_pos = row * MATRIX_SIZE + col; uint64_t mask = 1ULL << bit_pos; // If the bit is 0, it's not isolated if ((matrix & mask) == 0) { return 0; } // Check adjacent bits (up, down, left, right) if (row > 0 && (matrix & (mask >> MATRIX_SIZE))) return 0; // Up if (row < MATRIX_SIZE - 1 && (matrix & (mask << MATRIX_SIZE))) return 0; // Down if (col > 0 && (matrix & (mask >> 1))) return 0; // Left if (col < MATRIX_SIZE - 1 && (matrix & (mask << 1))) return 0; // Right // If none of the adjacent bits are 1, it's isolated return 1; } // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { for (int row = 0; row < MATRIX_SIZE; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { if (is_isolated(matrix, row, col)) { return 0; } } } return 1; } // Dynamic programming function to count unholy matrices uint64_t count_unholy(int rows, uint64_t prev_rows, uint64_t dp[][1 << 16]) { if (rows == MATRIX_SIZE) { return is_unholy(prev_rows); } if (dp[rows][prev_rows] != -1) { return dp[rows][prev_rows]; } uint64_t count = 0; for (uint64_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows + 2, next_rows, dp); } } return dp[rows][prev_rows] = count; } int main() { uint64_t dp[MATRIX_SIZE][1 << 16]; for (int i = 0; i < MATRIX_SIZE; i++) { for (int j = 0; j < (1 << 16); j++) { dp[i][j] = -1; } } uint64_t count = count_unholy(0, 0, dp); printf("Total number of unholy matrices: %llu\n", count); 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 67 68 69 70 71 72 | #include <stdio.h> #include <stdint.h> #define MATRIX_SIZE 8 #define TOTAL_BITS (MATRIX_SIZE * MATRIX_SIZE) // Function to check if a bit at (row, col) is isolated int is_isolated(uint64_t matrix, int row, int col) { int bit_pos = row * MATRIX_SIZE + col; uint64_t mask = 1ULL << bit_pos; // If the bit is 0, it's not isolated if ((matrix & mask) == 0) { return 0; } // Check adjacent bits (up, down, left, right) if (row > 0 && (matrix & (mask >> MATRIX_SIZE))) return 0; // Up if (row < MATRIX_SIZE - 1 && (matrix & (mask << MATRIX_SIZE))) return 0; // Down if (col > 0 && (matrix & (mask >> 1))) return 0; // Left if (col < MATRIX_SIZE - 1 && (matrix & (mask << 1))) return 0; // Right // If none of the adjacent bits are 1, it's isolated return 1; } // Function to check if a matrix is unholy int is_unholy(uint64_t matrix) { for (int row = 0; row < MATRIX_SIZE; row++) { for (int col = 0; col < MATRIX_SIZE; col++) { if (is_isolated(matrix, row, col)) { return 0; } } } return 1; } // Dynamic programming function to count unholy matrices uint64_t count_unholy(int rows, uint64_t prev_rows, uint64_t dp[][1 << 16]) { if (rows == MATRIX_SIZE) { return is_unholy(prev_rows); } if (dp[rows][prev_rows] != -1) { return dp[rows][prev_rows]; } uint64_t count = 0; for (uint64_t next_rows = 0; next_rows < (1 << 16); next_rows++) { uint64_t new_matrix = (prev_rows << 16) | next_rows; if (is_unholy(new_matrix)) { count += count_unholy(rows + 2, next_rows, dp); } } return dp[rows][prev_rows] = count; } int main() { uint64_t dp[MATRIX_SIZE][1 << 16]; for (int i = 0; i < MATRIX_SIZE; i++) { for (int j = 0; j < (1 << 16); j++) { dp[i][j] = -1; } } uint64_t count = count_unholy(0, 0, dp); printf("Total number of unholy matrices: %llu\n", count); 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 for the Program 1. **Define the Matrix Representation:** - Use an unsigned long to represent the 8x8 binary matrix. An 8x8 matrix has 64 bits, which can be comfortably stored in an unsigned long. 2. **Define the Unholy Check Function:** - Write a function `is_unholy(unsigned long matrix)` that returns 1 if the matrix is unholy and 0 otherwise. - This function will use bit manipulation to check for isolated 1s. It will iterate through each bit in the matrix, checking the adjacent bits to ensure there are no isolated 1s. 3. **Dynamic Programming Setup:** - Use dynamic programming to count the number of unholy matrices. - Define a recursive function `count_unholy(int rows, unsigned long current_matrix)` that counts the number of unholy matrices given the number of rows and the current matrix state. - Initialize the base case for 0 rows as 1. 4. **Recursive Enumeration:** - For each recursive call, enumerate all possible combinations of the next two rows (2^16 combinations). - For each combination, check if appending these rows to the current matrix results in an unholy matrix. - Recurse with the new matrix state and one less row. 5. **Main Function:** - Initialize the counting process with 8 rows and an empty matrix. - Print the total count of unholy matrices. ## Implementation 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 | #include <stdio.h> // Function to check if a given 8x8 matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { unsigned long bit = 1UL << (row * 8 + col); if (matrix & bit) { int isolated = 1; if (row > 0 && (matrix & (bit >> 8))) isolated = 0; if (row < 7 && (matrix & (bit << 8))) isolated = 0; if (col > 0 && (matrix & (bit >> 1))) isolated = 0; if (col < 7 && (matrix & (bit << 1))) isolated = 0; if (isolated) return 0; } } } return 1; } // Recursive function to count unholy matrices unsigned long count_unholy(int rows, unsigned long current_matrix) { if (rows == 0) { return is_unholy(current_matrix); } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { unsigned long new_matrix = current_matrix | (next_rows << ((8 - rows) * 8)); if (is_unholy(new_matrix)) { count += count_unholy(rows - 2, new_matrix); } } return count; } int main() { unsigned long result = count_unholy(8, 0); printf("Total number of unholy 8x8 matrices: %lu\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 | #include <stdio.h> // Function to check if a given 8x8 matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { unsigned long bit = 1UL << (row * 8 + col); if (matrix & bit) { int isolated = 1; if (row > 0 && (matrix & (bit >> 8))) isolated = 0; if (row < 7 && (matrix & (bit << 8))) isolated = 0; if (col > 0 && (matrix & (bit >> 1))) isolated = 0; if (col < 7 && (matrix & (bit << 1))) isolated = 0; if (isolated) return 0; } } } return 1; } // Recursive function to count unholy matrices unsigned long count_unholy(int rows, unsigned long current_matrix) { if (rows == 0) { return is_unholy(current_matrix); } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { unsigned long new_matrix = current_matrix | (next_rows << ((8 - rows) * 8)); if (is_unholy(new_matrix)) { count += count_unholy(rows - 2, new_matrix); } } return count; } int main() { unsigned long result = count_unholy(8, 0); printf("Total number of unholy 8x8 matrices: %lu\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 | #include <stdio.h> // Function to check if a given 8x8 matrix is unholy int is_unholy(unsigned long matrix) { for (int row = 0; row < 8; row++) { for (int col = 0; col < 8; col++) { unsigned long bit = 1UL << (row * 8 + col); if (matrix & bit) { int isolated = 1; if (row > 0 && (matrix & (bit >> 8))) isolated = 0; if (row < 7 && (matrix & (bit << 8))) isolated = 0; if (col > 0 && (matrix & (bit >> 1))) isolated = 0; if (col < 7 && (matrix & (bit << 1))) isolated = 0; if (isolated) return 0; } } } return 1; } // Recursive function to count unholy matrices unsigned long count_unholy(int rows, unsigned long current_matrix) { if (rows == 0) { return is_unholy(current_matrix); } unsigned long count = 0; for (unsigned long next_rows = 0; next_rows < (1UL << 16); next_rows++) { unsigned long new_matrix = current_matrix | (next_rows << ((8 - rows) * 8)); if (is_unholy(new_matrix)) { count += count_unholy(rows - 2, new_matrix); } } return count; } int main() { unsigned long result = count_unholy(8, 0); printf("Total number of unholy 8x8 matrices: %lu\n", result); 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 an 8x8 binary matrix. Each bit in the `unsigned long` will correspond to an entry in the matrix. - For an 8x8 matrix, we need 64 bits, which fits in an `unsigned long long` (assuming it is 64 bits). 2. **Check if a Matrix is Unholy**: - Implement a function `is_unholy` that takes an `unsigned long long` and checks if it is unholy by ensuring no isolated 1s are present. - Use bit-shifting and masking to check the neighbors of each bit. 3. **Dynamic Programming Approach**: - Use a recursive function to generate matrices row by row. - For each matrix with `r` rows, generate all possible configurations of the next two rows (since each row has 8 bits, there are 2^16 possible configurations for two rows). - Check for unholiness and recursively continue to build the matrix. 4. **Count the Number of Unholy Matrices**: - Use a global counter to keep track of the number of unholy matrices. ### Implementation Below is the implementation 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 | #include <stdio.h> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 // Check if a given matrix (64-bit unsigned long long) is unholy bool is_unholy(unsigned long long matrix) { // Check each bit in the matrix for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix & (1ULL << i)) != 0) { // Check neighbors (up, down, left, right) bool has_neighbor = false; if (i >= ROW_SIZE && (matrix & (1ULL << (i - ROW_SIZE)))) has_neighbor = true; // Up if (i < MATRIX_SIZE - ROW_SIZE && (matrix & (1ULL << (i + ROW_SIZE)))) has_neighbor = true; // Down if (i % ROW_SIZE > 0 && (matrix & (1ULL << (i - 1)))) has_neighbor = true; // Left if (i % ROW_SIZE < ROW_SIZE - 1 && (matrix & (1ULL << (i + 1)))) has_neighbor = true; // Right if (!has_neighbor) return false; } } return true; } // Recursive function to count unholy matrices void count_unholy_matrices(int row, unsigned long long current_matrix, int *count) { if (row == 8) { if (is_unholy(current_matrix)) { (*count)++; } return; } // Generate all 2^16 configurations for the next two rows for (unsigned long next_rows = 0; next_rows < (1ULL << 16); next_rows++) { unsigned long long new_matrix = current_matrix | (next_rows << (row * ROW_SIZE)); count_unholy_matrices(row + 2, new_matrix, count); } } // Main function int main() { int count = 0; unsigned long long initial_matrix = 0; // Start the recursion with the first row count_unholy_matrices(0, initial_matrix, &count); printf("Total number of unholy 8x8 matrices: %d\n", count); 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> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 // Check if a given matrix (64-bit unsigned long long) is unholy bool is_unholy(unsigned long long matrix) { // Check each bit in the matrix for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix & (1ULL << i)) != 0) { // Check neighbors (up, down, left, right) bool has_neighbor = false; if (i >= ROW_SIZE && (matrix & (1ULL << (i - ROW_SIZE)))) has_neighbor = true; // Up if (i < MATRIX_SIZE - ROW_SIZE && (matrix & (1ULL << (i + ROW_SIZE)))) has_neighbor = true; // Down if (i % ROW_SIZE > 0 && (matrix & (1ULL << (i - 1)))) has_neighbor = true; // Left if (i % ROW_SIZE < ROW_SIZE - 1 && (matrix & (1ULL << (i + 1)))) has_neighbor = true; // Right if (!has_neighbor) return false; } } return true; } // Recursive function to count unholy matrices void count_unholy_matrices(int row, unsigned long long current_matrix, int *count) { if (row == 8) { if (is_unholy(current_matrix)) { (*count)++; } return; } // Generate all 2^16 configurations for the next two rows for (unsigned long next_rows = 0; next_rows < (1ULL << 16); next_rows++) { unsigned long long new_matrix = current_matrix | (next_rows << (row * ROW_SIZE)); count_unholy_matrices(row + 2, new_matrix, count); } } // Main function int main() { int count = 0; unsigned long long initial_matrix = 0; // Start the recursion with the first row count_unholy_matrices(0, initial_matrix, &count); printf("Total number of unholy 8x8 matrices: %d\n", count); 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> #include <stdbool.h> #define MATRIX_SIZE 64 #define ROW_SIZE 8 // Check if a given matrix (64-bit unsigned long long) is unholy bool is_unholy(unsigned long long matrix) { // Check each bit in the matrix for (int i = 0; i < MATRIX_SIZE; i++) { if ((matrix & (1ULL << i)) != 0) { // Check neighbors (up, down, left, right) bool has_neighbor = false; if (i >= ROW_SIZE && (matrix & (1ULL << (i - ROW_SIZE)))) has_neighbor = true; // Up if (i < MATRIX_SIZE - ROW_SIZE && (matrix & (1ULL << (i + ROW_SIZE)))) has_neighbor = true; // Down if (i % ROW_SIZE > 0 && (matrix & (1ULL << (i - 1)))) has_neighbor = true; // Left if (i % ROW_SIZE < ROW_SIZE - 1 && (matrix & (1ULL << (i + 1)))) has_neighbor = true; // Right if (!has_neighbor) return false; } } return true; } // Recursive function to count unholy matrices void count_unholy_matrices(int row, unsigned long long current_matrix, int *count) { if (row == 8) { if (is_unholy(current_matrix)) { (*count)++; } return; } // Generate all 2^16 configurations for the next two rows for (unsigned long next_rows = 0; next_rows < (1ULL << 16); next_rows++) { unsigned long long new_matrix = current_matrix | (next_rows << (row * ROW_SIZE)); count_unholy_matrices(row + 2, new_matrix, count); } } // Main function int main() { int count = 0; unsigned long long initial_matrix = 0; // Start the recursion with the first row count_unholy_matrices(0, initial_matrix, &count); printf("Total number of unholy 8x8 matrices: %d\n", count); return 0; } |
Timeout: function took too long to complete
Testing if the previous output contains the string 1121231537486377866
: False