Sorting multiple specified ranges in an array

Question

Suppose I have an array with following elements

int arr2[]={21,31,41,51,54,29,15,18,19,16,17};

and I have second array arr

int arr[]={4,2,5};

Now I want to sort arr2 with the help of arr in ACS in such a way that it gets sorted like this and final array becomes

Final array should be 21,31,41,51,29,54,15,16,17,18,19

note that arr[0]=4 hence first four elements are sorted in ASC 21,31,41,51

then arr[1]=2 hence next two elements are sorted in ACS, so it becomes 21,31,41,51,29,54

then arr[2]=5 hence next five elements will be sorted in ASC, so it becomes 21,31,41,51,29,54,15,16,17,18,19

now final array becomes 21,31,41,51,29,54,15,16,17,18,19

how can I do this kind of sorting ?

Code I am using to do this is

int arr2[]={21,31,41,51,54,29,15,18,19,16,17};
       int arr[]={4,2,5};

I am able to achieve the result with below code but the problem is I can't make it short when the number of array/elements are not known.

for (i=0;i<4-1;i++) 
         {
              for (j=i+1;j<4; j++)
              {
                   if( arr[i] > arr[j] )       
                   {
                           temp = arr[i];   
                           arr[i] = arr[j];
                           arr[j] = temp; 
                    }           
              }
         }

       for (i=5;i<6-1;i++) 
         {
              for (j=i+1;j<7; j++)
              {
                   if( arr[i] > arr[j] )       
                   {
                           temp = arr[i];   
                           arr[i] = arr[j];
                           arr[j] = temp; 
                    }           
              }
         }

       for (i=7;i<11-1;i++) 
         {
              for (j=i+1;j<10; j++)
              {
                   if( arr[i] > arr[j] )       
                   {
                           temp = arr[i];   
                           arr[i] = arr[j];
                           arr[j] = temp; 
                    }           
              }
         }

Answer 1

http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#sort-byte:A-int-int-

There is Arrays.sort method which accepts ranges. Solution to your problem becomes:

int arr2[]={21,31,41,51,54,29,15,18,19,16,17};
int arr[]={4,2,5};

int start_index = 0;
for(int i=0; i < arr.length; ++i)
{
  Arrays.sort(arr2,start_index,start_index+arr[i]);
  start_index += arr[i];
}