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  1. // OpenMP Implementation
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4. #include <string.h>
  5. #include <omp.h>
  6. #include <time.h>
  7.  
  8. #define ROWS 1000
  9. #define COLUMNS 1000
  10.  
  11. // Function to check if a string is a palindrome
  12. int is_palindrome(char *str, int len) {
  13.     for (int i = 0; i < len / 2; i++) {
  14.         if (str[i] != str[len - i - 1]) {
  15.             return 0;
  16.         }
  17.     }
  18.     return 1;
  19. }
  20.  
  21. int main() {
  22.     char matrix[ROWS][COLUMNS];
  23.     int n = 3; // Change this to the palindrome length you want to search for
  24.     int total_palindromes = 0;
  25.  
  26.     // Generate the matrix with random characters
  27.     srand(time(NULL));
  28.     for (int i = 0; i < ROWS; i++) {
  29.         for (int j = 0; j < COLUMNS; j++) {
  30.             matrix[i][j] = (rand() % 26) + 'A';
  31.         }
  32.     }
  33.  
  34.     for (int threads = 1; threads <= 8; threads++) {
  35.         omp_set_num_threads(threads);
  36.         int palindrome_count = 0;
  37.         double start_time = omp_get_wtime();
  38.  
  39.         #pragma omp parallel for reduction(+:palindrome_count)
  40.         for (int i = 0; i < ROWS; i++) {
  41.             for (int j = 0; j < COLUMNS; j++) {
  42.                 char temp[n + 1];
  43.  
  44.                 // Check right-to-left
  45.                 if (j >= n - 1) {
  46.                     for (int k = 0; k < n; k++) {
  47.                         temp[k] = matrix[i][j - k];
  48.                     }
  49.                     temp[n] = '\0';
  50.                     if (is_palindrome(temp, n)) {
  51.                         palindrome_count++;
  52.                     }
  53.                 }
  54.  
  55.                 // Check up-to-down
  56.                 if (i <= ROWS - n) {
  57.                     for (int k = 0; k < n; k++) {
  58.                         temp[k] = matrix[i + k][j];
  59.                     }
  60.                     temp[n] = '\0';
  61.                     if (is_palindrome(temp, n)) {
  62.                         palindrome_count++;
  63.                     }
  64.                 }
  65.  
  66.                 // Check diagonally up-to-down
  67.                 if (i <= ROWS - n && j >= n - 1) {
  68.                     for (int k = 0; k < n; k++) {
  69.                         temp[k] = matrix[i + k][j - k];
  70.                     }
  71.                     temp[n] = '\0';
  72.                     if (is_palindrome(temp, n)) {
  73.                         palindrome_count++;
  74.                     }
  75.                 }
  76.             }
  77.         }
  78.  
  79.         double end_time = omp_get_wtime();
  80.         total_palindromes = palindrome_count;
  81.         printf("%d palindromes of size %d found in %.6f s using %d threads.\n",
  82.                total_palindromes, n, end_time - start_time, threads);
  83.     }
  84.  
  85.     return 0;
  86. }
  87.  
Success #stdin #stdout #stderr 0.3s 40280KB
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Standard input is empty
stdout
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Standard output is empty
stderr
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Error: unexpected '/' in "/"
Execution halted
https://ideone.com/oOMlhm
language:
R (R 3.5.2)
created:
10 days ago
visibility:
public

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