/*
 * @brief  selection sort
 */
 void
 selection_sort(int a[], int n)
 {
   int i, j, min, tmp;
   
   for (i = 0; i < n - 1; ++i) {
     min = i;
     for (j = i+1; j < n; ++j) {
       if (a[j] < a[min]) {
         min = j;
       }
     }
     if (min != i) {
       tmp = a[min];
       a[min] = a[i];
       a[i] = tmp;  
     }        
   }
 }

 /* @brief insetion sort
 * insert the new element to the sorted subarray
 */
 void
 insertion_sort(int a[], int n)
 {
   int i, j, num;
 
   for (i = 1; i < n; ++i) {
     num = a[i];
     for (j = i - 1; j >= 0 && a[j] > num; --j)
       a[j+1] = a[j];
     a[j+1] = num;
   }
 }

 /* @brief  bubble sort
 * move the smallest element to the front in every single loop
 */
 void
 bubble_sort(int a[], int n)
 {
   int i, j, tmp;
 
   for (i = 0; i < n; ++i) {
     for (j = n - 1; j > i; --j) {
       if (a[j] < a[j-1]) {
         tmp = a[j];
         a[j] = a[j-1];
         a[j-1] = tmp;
       }
     }
   }
 }