a) 冒泡

public static void mp(int a[]) {
   int swap = 0;
   for (int i = 0; i < a.length; i++) {
      for (int j = i; j < a.length; j++) {
         if (a[j] > a[i]) {
         swap = a[i];
         a[i] = a[j];
         a[j] = swap;
      }
   }
}
System.out.println(Arrays.toString(a));
}

b)二分查找

public static int ef(int a[], int tag) {
   int first = 0;
   int end = a.length;
   for (int i = 0; i < a.length; i++) {
      int middle = (first + end) / 2;
      if (tag == a[middle]) {
         return middle;
      }
      if (tag > a[middle]) {
         first = middle + 1;
      }
      if (tag < a[middle]) {
         end = middle - 1;
      }
   }
return 0;
}