几种排序算法小结

插入排序， O(n^2), 从头到尾， 将较小的放在前面

/* insertion sort ascending order */
 
#include <stdio.h>
 
int main()
{
  int n, array[1000], c, d, t;
 
  printf("Enter number of elements\n");
  scanf("%d", &n);
 
  printf("Enter %d integers\n", n);
 
  for (c = 0; c < n; c++) {
    scanf("%d", &array[c]);
  }
 
  for (c = 1 ; c <= n - 1; c++) {
    d = c;
 
    while ( d > 0 && array[d] < array[d-1]) {
      t          = array[d];
      array[d]   = array[d-1];
      array[d-1] = t;
 
      d--;
    }
  }
 
  printf("Sorted list in ascending order:\n");
 
  for (c = 0; c <= n - 1; c++) {
    printf("%d\n", array[c]);
  }
 
  return 0;
}

 冒泡排序， O(n^2), 将较大的放在后面。

/* Bubble sort code */
 
#include <stdio.h>
 
int main()
{
  int array[100], n, c, d, swap;
 
  printf("Enter number of elements\n");
  scanf("%d", &n);
 
  printf("Enter %d integers\n", n);
 
  for (c = 0; c < n; c++)
    scanf("%d", &array[c]);
 
  for (c = 0 ; c < ( n - 1 ); c++)
  {
    for (d = 0 ; d < n - c - 1; d++)
    {
      if (array[d] > array[d+1]) /* For decreasing order use < */
      {
        swap       = array[d];
        array[d]   = array[d+1];
        array[d+1] = swap;
      }
    }
  }
 
  printf("Sorted list in ascending order:\n");
 
  for ( c = 0 ; c < n ; c++ )
     printf("%d\n", array[c]);
 
  return 0;
}