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; } |
To solve this problem, we need to count the number of 16-bit patterns that remain unchanged after applying a specific transformation. The transformation involves modifying an 8x8 grid based on the values of neighboring cells. The goal is to determine how many initial configurations remain unchanged after one iteration of this transformation. ### Approach 1. **Grid Initialization**: Convert a 16-bit integer into an 8x8 grid. The 16-bit integer is split into four 4-bit chunks, each placed in specific positions within the grid. 2. **Transformation Process**: For each cell in the inner 6x6 grid (excluding the outermost layer), check if all four neighboring cells (top, bottom, left, right) are zero. If they are and the current cell is 1, set the current cell to 0. 3. **Count Unchanged Configurations**: After applying the transformation, check if the grid remains unchanged. Count how many such configurations exist. ### Solution Code
1 | int count(){int c=0,i,p,k;for(i=0;i<1<<16;i++){unsigned long long a=0,t;for(k=0;k<4;k++)a|=(i&(15<<4*k))<<(9+4*k);t=a;for(p=9;p<55;p++)if(p%8%7&&((t>>(p-8)&1)+(t>>(p-1)&1)+(t>>(p+8)&1)+(t>>(p+1)&1))==0&&(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,i,p,k;for(i=0;i<1<<16;i++){unsigned long long a=0,t;for(k=0;k<4;k++)a|=(i&(15<<4*k))<<(9+4*k);t=a;for(p=9;p<55;p++)if(p%8%7&&((t>>(p-8)&1)+(t>>(p-1)&1)+(t>>(p+8)&1)+(t>>(p+1)&1))==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 | int count(){int c=0,i,p,k;for(i=0;i<1<<16;i++){unsigned long long a=0,t;for(k=0;k<4;k++)a|=(i&(15<<4*k))<<(9+4*k);t=a;for(p=9;p<55;p++)if(p%8%7&&((t>>(p-8)&1)+(t>>(p-1)&1)+(t>>(p+8)&1)+(t>>(p+1)&1))==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