Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
### Step 1: Function Explanation The function `count` essentially iterates over all possible 16-bit numbers (from `0` to `65535`), treating each number as a representation of 4 rows of 4 bits. It then constructs a 64-bit number by placing these 4 rows of 4 bits into specific positions in an 8x8 grid (64 bits). For each of these 64-bit numbers, it checks every cell that is not on the border of the grid. If a cell has all four neighboring cells as `0` and the cell itself is `1`, it sets the cell to `0`. Finally, it counts how many of these 64-bit numbers remain unchanged after this process. ### Step 2: Ways to Shorten the Function 1. **Inline Constants**: Replace named constants `ROWS` and `COLS` with their values directly. 2. **Combine Declarations**: Combine variable declarations where possible. 3. **Reduce Loop Variables**: Use single-character variable names where appropriate. 4. **Eliminate Redundant Variables**: Remove any unnecessary temporary variables. 5. **Minimize Operations**: Use bitwise operations efficiently to minimize lines of code. ### Step 3: Shortened Function
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c = 0; for (int i = 0; i < 1<<16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int r = 1; r < 7; r++) for (int j = 1; j < 7; j++) { int p = r * 8 + j; if (((t >> p) & 1) && !((t >> (p - 8) & 1) | (t >> (p - 1) & 1) | (t >> (p + 8) & 1) | (t >> (p + 1) & 1))) a &= ~(1ULL << p); } c += (a == t); } return c; } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c = 0; for (int i = 0; i < 1<<16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int r = 1; r < 7; r++) for (int j = 1; j < 7; j++) { int p = r * 8 + j; if (((t >> p) & 1) && !((t >> (p - 8) & 1) | (t >> (p - 1) & 1) | (t >> (p + 8) & 1) | (t >> (p + 1) & 1))) a &= ~(1ULL << p); } c += (a == t); } return c; } |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c = 0; for (int i = 0; i < 1<<16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int r = 1; r < 7; r++) for (int j = 1; j < 7; j++) { int p = r * 8 + j; if (((t >> p) & 1) && !((t >> (p - 8) & 1) | (t >> (p - 1) & 1) | (t >> (p + 8) & 1) | (t >> (p + 1) & 1))) a &= ~(1ULL << p); } c += (a == t); } return c; } |
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 | int count() { int c = 0; for (int i = 0; i < 1<<16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int r = 1; r < 7; r++) for (int j = 1; j < 7; j++) { int p = r * 8 + j; if (((t >> p) & 1) && !((t >> (p - 8) & 1) | (t >> (p - 1) & 1) | (t >> (p + 8) & 1) | (t >> (p + 1) & 1))) a &= ~(1ULL << p); } c += (a == t); } return c; } #include<stdio.h> #include<stdlib.h> int main() { int answer = count(); int expected = 27488; if (answer != expected) { printf("Wrong answer; got %d instead of %d.\n", answer, expected); exit(1); } printf("All tests passed\n"); } |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Resulting in output: True
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
### Explanation of the Function: The function `count` iterates through all possible 16-bit integers (`i` from `0` to `65535`), treating each as a 4x4 grid of bits. It then embeds this 4x4 grid into an 8x8 grid at a specific location and performs a simulation to modify the grid based on the sum of the neighbors of each cell. If a cell has all four neighbors as `0` and the cell itself is `1`, it turns that cell off. Finally, it counts how many of the initial grids remain unchanged after this process. ### Ways to Shorten the Code: 1. **Remove Unused Variables**: The variables `ROWS` and `COLS` are constants and can be inlined. 2. **Bit Operations**: Simplify bit manipulations and calculations using more compact expressions. 3. **Loop Unrolling**: Reduce the number of loops if possible, or combine some operations. 4. **Inline Calculations**: Inline some of the calculations to avoid temporary variables. 5. **Reduce Redundancy**: Eliminate redundant or repetitive code. ### Shortened Code: Here's a more compact version of the function, attempting to stay within the 300-byte limit:
1 2 3 4 5 6 7 8 9 10 11 12 13 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int i = 1; i < 7; i++) for (int j = 1; j < 7; j++) { int p = i * 8 + j, sum = ((t >> (p - 8)) & 1) + ((t >> (p - 1)) & 1) + ((t >> (p + 8)) & 1) + ((t >> (p + 1)) & 1); if (sum == 0 && (t >> p) & 1) a &= ~(1ULL << p); } c += (a == t); } return c; } |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int i = 1; i < 7; i++) for (int j = 1; j < 7; j++) { int p = i * 8 + j, sum = ((t >> (p - 8)) & 1) + ((t >> (p - 1)) & 1) + ((t >> (p + 8)) & 1) + ((t >> (p + 1)) & 1); if (sum == 0 && (t >> p) & 1) a &= ~(1ULL << p); } c += (a == t); } return c; } |
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 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int i = 1; i < 7; i++) for (int j = 1; j < 7; j++) { int p = i * 8 + j, sum = ((t >> (p - 8)) & 1) + ((t >> (p - 1)) & 1) + ((t >> (p + 8)) & 1) + ((t >> (p + 1)) & 1); if (sum == 0 && (t >> p) & 1) a &= ~(1ULL << p); } c += (a == t); } return c; } #include<stdio.h> #include<stdlib.h> int main() { int answer = count(); int expected = 27488; if (answer != expected) { printf("Wrong answer; got %d instead of %d.\n", answer, expected); exit(1); } printf("All tests passed\n"); } |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Resulting in output: True
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
### 1. Explanation of the Function The function `count` iterates over all 16-bit integers and performs the following operations for each integer: 1. **Transformation**: It transforms the integer into a 64-bit integer by shifting and combining nibbles (4-bit segments). 2. **Simulation**: It simulates a cellular automaton-like process on an 8x8 grid: - For each cell in the 8x8 grid (excluding the border cells), it checks the values of its four neighbors. - If all neighbors are 0 and the cell itself is 1, the cell is turned off (set to 0). 3. **Count Update**: It increments a count if the transformed integer remains the same after the simulation. ### 2. Ways to Make the Function Shorter - **Reduce Variable Declarations**: Compress variable declarations and initialization. - **Combine Loops**: Merge nested loops where possible. - **Inline Calculations**: Perform inline calculations instead of using separate variables for intermediate values. - **Remove Redundant Code**: Remove unnecessary steps or checks. ### 3. Write the Function as Short as Possible Here's the function compressed and optimized for brevity:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int p, q, k = 1; k < 64; k++) { if (k % 8 && k % 8 != 7 && k > 7 && k < 56) { p = k - 8, q = k + 8; if (((t >> k) & 1) && !((t >> p) & 1) && !((t >> k - 1) & 1) && !((t >> q) & 1) && !((t >> k + 1) & 1)) a &= ~(1ULL << k); } } c += (a == t); } return c; } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int k = 1; k < 63; k++) { if (k % 8 && k % 8 != 7 && k > 7 && k < 56) { if (((t >> k) & 1) && !((t >> (k - 8)) & 1) && !((t >> (k - 1)) & 1) && !((t >> (k + 8)) & 1) && !((t >> (k + 1)) & 1)) a &= ~(1ULL << k); } } c += (a == t); } return c; } |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int k = 1; k < 63; k++) { if (k % 8 && k % 8 != 7 && k > 7 && k < 56) { if (((t >> k) & 1) && !((t >> (k - 8)) & 1) && !((t >> (k - 1)) & 1) && !((t >> (k + 8)) & 1) && !((t >> (k + 1)) & 1)) a &= ~(1ULL << k); } } c += (a == t); } return c; } |
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 | int count() { int c = 0; for (int i = 0; i < 1 << 16; i++) { unsigned long long a = ((i & 0xf) << 9) | ((i & 0xf0) << 13) | ((i & 0xf00) << 17) | ((i & 0xf000) << 21), t = a; for (int k = 1; k < 63; k++) { if (k % 8 && k % 8 != 7 && k > 7 && k < 56) { if (((t >> k) & 1) && !((t >> (k - 8)) & 1) && !((t >> (k - 1)) & 1) && !((t >> (k + 8)) & 1) && !((t >> (k + 1)) & 1)) a &= ~(1ULL << k); } } c += (a == t); } return c; } #include<stdio.h> #include<stdlib.h> int main() { int answer = count(); int expected = 27488; if (answer != expected) { printf("Wrong answer; got %d instead of %d.\n", answer, expected); exit(1); } printf("All tests passed\n"); } |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Resulting in output: True
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
### Explanation of the Function The function `count` performs the following tasks: 1. It iterates through all possible 16-bit integers (from 0 to 65535). 2. For each integer, it constructs a 64-bit integer by placing the 4-bit nibbles of the integer into specific positions within the 64-bit integer. 3. It then iterates over the 64-bit integer, treating it as an 8x8 grid of bits. 4. For each cell in the grid (except the border cells), it checks if the cell is surrounded by zeros and if the cell itself is one. If so, it updates the cell to zero. 5. After processing the grid, it compares the updated grid with the initial grid. If they are the same, it increments a counter. 6. Finally, it returns the counter. ### Steps to Shorten the Function 1. **Remove Unnecessary Variables**: We can remove the `ROWS` and `COLS` variables since they are always 8. 2. **Inline Calculations**: We can combine multiple lines into one where possible. 3. **Use Ternary Operators**: Use ternary operators to simplify conditional statements. 4. **Minimize Loop Variables**: Use single-letter variable names to save bytes. 5. **Remove Whitespace**: Remove unnecessary whitespace and comments. ### Shortened Function
1 | int count(){int c=0;for(int i=0;i<1<<16;i++){unsigned long long a=((i&0xf)<<9)|((i&0xf0)<<(13))|((i&0xf00)<<(17))|((i&0xf000)<<(21)),t=a;for(int i=1;i<7;i++)for(int j=1;j<7;j++){int p=i*8+j,tp=(i-1)*8+j,lp=i*8+j-1,bp=(i+1)*8+j,rp=i*8+j+1;if(!(((t>>tp)&1)+((t>>lp)&1)+((t>>bp)&1)+((t>>rp)&1))&&((t>>p)&1))a&=~(1ULL<<p);}c+=(a==t);}return c;} |
1 | int count(){int c=0;for(int i=0;i<1<<16;i++){unsigned long long a=((i&0xf)<<9)|((i&0xf0)<<(13))|((i&0xf00)<<(17))|((i&0xf000)<<(21)),t=a;for(int i=1;i<7;i++)for(int j=1;j<7;j++){int p=i*8+j,tp=(i-1)*8+j,lp=i*8+j-1,bp=(i+1)*8+j,rp=i*8+j+1;if(!(((t>>tp)&1)+((t>>lp)&1)+((t>>bp)&1)+((t>>rp)&1))&&((t>>p)&1))a&=~(1ULL<<p);}c+=(a==t);}return c;} |
I extracted the following code from that output:
1 | int count(){int c=0;for(int i=0;i<1<<16;i++){unsigned long long a=((i&0xf)<<9)|((i&0xf0)<<(13))|((i&0xf00)<<(17))|((i&0xf000)<<(21)),t=a;for(int i=1;i<7;i++)for(int j=1;j<7;j++){int p=i*8+j,tp=(i-1)*8+j,lp=i*8+j-1,bp=(i+1)*8+j,rp=i*8+j+1;if(!(((t>>tp)&1)+((t>>lp)&1)+((t>>bp)&1)+((t>>rp)&1))&&((t>>p)&1))a&=~(1ULL<<p);}c+=(a==t);}return c;} |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | int count(){int c=0;for(int i=0;i<1<<16;i++){unsigned long long a=((i&0xf)<<9)|((i&0xf0)<<(13))|((i&0xf00)<<(17))|((i&0xf000)<<(21)),t=a;for(int i=1;i<7;i++)for(int j=1;j<7;j++){int p=i*8+j,tp=(i-1)*8+j,lp=i*8+j-1,bp=(i+1)*8+j,rp=i*8+j+1;if(!(((t>>tp)&1)+((t>>lp)&1)+((t>>bp)&1)+((t>>rp)&1))&&((t>>p)&1))a&=~(1ULL<<p);}c+=(a==t);}return c;} #include<stdio.h> #include<stdlib.h> int main() { int answer = count(); int expected = 27488; if (answer != expected) { printf("Wrong answer; got %d instead of %d.\n", answer, expected); exit(1); } printf("All tests passed\n"); } |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Resulting in output: False
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
Code golf this function to be a lot shorter. You only get points if it's <300 bytes (not counting whitespace). Keep the function named `count`.
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 | int count() { int ROWS = 8; int COLS = 8; int count = 0; for (int i = 0; i < 1<<16; i++) { long long unsigned int array = ((i & 0xf) << 9) | ((i & 0xf0) << (9 + 8 - 4)) | ((i & 0xf00) << (9 + 8 - 4 + 8 - 4)) | ((i & 0xf000) << (9 + 8 - 4 + 8 - 4 + 8 - 4)); long long unsigned int init = array; long long unsigned int temp = array; for (int i = 1; i < ROWS - 1; i++) { for (int j = 1; j < COLS - 1; j++) { // Calculate bit positions int pos = i * COLS + j; int topPos = (i - 1) * COLS + j; int leftPos = i * COLS + (j - 1); int bottomPos = (i + 1) * COLS + j; int rightPos = i * COLS + (j + 1); // Get the values of the neighbors int cell = (temp >> pos) & 1; int top = (temp >> topPos) & 1; int left = (temp >> leftPos) & 1; int bottom = (temp >> bottomPos) & 1; int right = (temp >> rightPos) & 1; // Sum the values of the neighbors int sum = top + left + bottom + right; // Update the cell if all neighbors are 0 and the cell itself is 1 if (sum == 0 && cell == 1) { array &= ~(1ULL << pos); } } } count += (init == array); } return count; } |
## Explanation The function `count` essentially runs a simulation on a grid of size 8x8, where it iterates over all possible 16-bit configurations, treating each 4-bit segment as a 4x4 block within the 8x8 grid. For each configuration, it checks certain conditions in a neighborhood of cells and updates the grid accordingly. Specifically, it checks if all neighbors of a cell are 0 and if the cell itself is 1, then it sets that cell to 0. Finally, it counts how many initial configurations remain unchanged after the update. ## Steps to Shorten the Function 1. **Remove Redundant Variables**: - `ROWS` and `COLS` are always 8, so replace them with `8`. - Combine declarations and initializations where possible. 2. **Inline Calculations**: - Simplify nested loops and inline calculations directly within the loop condition or body. 3. **Bitwise Operations**: - Use more concise bitwise operations to handle the grid transformations. 4. **Minimize Variable Use**: - Reduce the number of temporary variables and leverage compound expressions. ## Shortened Function
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c=0; for (int i=0; i<65536; i++) { unsigned long long a=((i&15)<<9)|((i&240)<<13)|((i&3840)<<17)|((i&61440)<<21),t=a; for (int i=1; i<7; i++) for (int j=1; j<7; j++) { int p=i*8+j; int s=!!(t&(1ULL<<(p-8)))+!!(t&(1ULL<<(p-1)))+!!(t&(1ULL<<(p+8)))+!!(t&(1ULL<<(p+1))); if (!s&&(t&(1ULL<<p))) a&=~(1ULL<<p); } c+=(a==t); } return c; } |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c=0; for (int i=0; i<65536; i++) { unsigned long long a=((i&15)<<9)|((i&240)<<13)|((i&3840)<<17)|((i&61440)<<21),t=a; for (int i=1; i<7; i++) for (int j=1; j<7; j++) { int p=i*8+j; int s=!!(t&(1ULL<<(p-8)))+!!(t&(1ULL<<(p-1)))+!!(t&(1ULL<<(p+8)))+!!(t&(1ULL<<(p+1))); if (!s&&(t&(1ULL<<p))) a&=~(1ULL<<p); } c+=(a==t); } return c; } |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | int count() { int c=0; for (int i=0; i<65536; i++) { unsigned long long a=((i&15)<<9)|((i&240)<<13)|((i&3840)<<17)|((i&61440)<<21),t=a; for (int i=1; i<7; i++) for (int j=1; j<7; j++) { int p=i*8+j; int s=!!(t&(1ULL<<(p-8)))+!!(t&(1ULL<<(p-1)))+!!(t&(1ULL<<(p+8)))+!!(t&(1ULL<<(p+1))); if (!s&&(t&(1ULL<<p))) a&=~(1ULL<<p); } c+=(a==t); } return c; } |
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 | int count() { int c=0; for (int i=0; i<65536; i++) { unsigned long long a=((i&15)<<9)|((i&240)<<13)|((i&3840)<<17)|((i&61440)<<21),t=a; for (int i=1; i<7; i++) for (int j=1; j<7; j++) { int p=i*8+j; int s=!!(t&(1ULL<<(p-8)))+!!(t&(1ULL<<(p-1)))+!!(t&(1ULL<<(p+8)))+!!(t&(1ULL<<(p+1))); if (!s&&(t&(1ULL<<p))) a&=~(1ULL<<p); } c+=(a==t); } return c; } #include<stdio.h> #include<stdlib.h> int main() { int answer = count(); int expected = 27488; if (answer != expected) { printf("Wrong answer; got %d instead of %d.\n", answer, expected); exit(1); } printf("All tests passed\n"); } |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Resulting in output: False