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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. void quicksort(double *A, int len);
  5.  
  6. int main (void) {
  7.   int n = 10000000;
  8.   double *a = (double*)malloc(n * sizeof (double));
  9.  
  10.   int i;
  11.   for (i = 0; i < n; i++) {
  12.     a[i] = rand();
  13.   }
  14.  
  15. /* 
  16.   double a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1};
  17.   int n = sizeof a / sizeof a[0];
  18.   int i;
  19.   for (i = 0; i < n; i++) {
  20.     printf("%d ", a[i]);
  21.   }
  22.   printf("\n");
  23.  */
  24.   quicksort(a, n);
  25.  /*
  26.   for (i = 0; i < n; i++) {
  27.     printf("%f ", a[i]);
  28.   }
  29.   printf("\n");
  30.  */
  31.   return 0;
  32. }
  33.  
  34. void quicksort(double *A, int len) {
  35.   if (len < 2) return;
  36.  
  37.   int pivot = A[len / 2];
  38.  
  39.   int i, j;
  40.   for (i = 0, j = len - 1; ; i++, j--) {
  41.     while (A[i] < pivot) i++;
  42.     while (A[j] > pivot) j--;
  43.  
  44.     if (i >= j) break;
  45.  
  46.     double temp = A[i];
  47.     A[i]     = A[j];
  48.     A[j]     = temp;
  49.   }
  50.  
  51.   quicksort(A, i);
  52.   quicksort(A + i, len - i);
  53. }
  54.  
Success #stdin #stdout 1.03s 79344KB
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https://ideone.com/jX2SGr
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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