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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <omp.h>
  4.  
  5. void prefix_sum(int* input, int* output, int n) {
  6.     output[0] = input[0];  // Initialize the first element
  7.  
  8.     #pragma omp parallel
  9.     {
  10.         // Each thread works in parallel on different sections
  11.         #pragma omp for
  12.         for (int i = 1; i < n; i++) {
  13.             output[i] = output[i - 1] + input[i];
  14.         }
  15.     }
  16. }
  17.  
  18. int main() {
  19.     int n;
  20.  
  21.     // Get the size of the array from the user
  22.     printf("Enter the size of the array: ");
  23.     scanf("%d", &n);
  24.  
  25.     int* input = (int*)malloc(n * sizeof(int));
  26.     int* output = (int*)malloc(n * sizeof(int));
  27.  
  28.     // Initialize the input array with values from 1 to n
  29.     for (int i = 0; i < n; i++) {
  30.         input[i] = i + 1;
  31.     }
  32.  
  33.     // Calculate prefix sums
  34.     prefix_sum(input, output, n);
  35.  
  36.     // Output the result
  37.     printf("Prefix sums:\n");
  38.     for (int i = 0; i < 10 && i < n; i++) {
  39.         printf("%d ", output[i]);
  40.     }
  41.     printf("\n");
  42.  
  43.     // Free dynamically allocated memory
  44.     free(input);
  45.     free(output);
  46.  
  47.     return 0;
  48. }
  49.  
Success #stdin #stdout 0s 5296KB
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stdin
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Standard input is empty
stdout
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Enter the size of the array: Prefix sums:
1 3 6 10 15 21 28 36 45 55
https://ideone.com/Rdl4oD
language:
C (gcc 8.3)
created:
5 days ago
visibility:
public

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