CMI2019-A-9

Question

The next two questions refer to the following program.

In the code below reverse$(A,i,j)$ takes an array $A,$ indices $i$ and $j$ with $i\leq j,$ and reverses the segment $A[i],A[i+1],\cdots,A[j].$ For instance if $A=[0,1,2,3,4,5,6,7]$ then, after we apply reverse$(A,3,6),$ the contents of the array will be $A=[0,1,2,6,5,4,3,7].$

function mystery (A[0...99]) {
  int i, j, m;
  for (i = 0; i < 100; i++) {
    m = i;
  for (j = i; j < 100; j++) {
    if (A[j] > A[m]) {
        m = j;
       }
     }
     reverse(A,i,m);
   }
   return;
 }

When the procedure terminates, the array A has been:

• A. Sorted in descending order
• B. Sorted in ascending order
• C. Reversed
• D. Left unaltered

Comments

Where are the next two questions??

Answer 1

 

Just take a simple example as : - arr : 3 5 1 2 4 6 

 For outer loop when i=0,m=0 and now internal loop execute from j=i to length of arr and check for each element greatest element in the array form j=i to length of array, and save its index in the variable m. Now reverse(A,0,m) will just reverse the array from the index i to m so the greatest element will now become the first element and 

So on :

 

Pic1 

 

Caption

 

Answer 2

Here we are given 100 elements in the array with indices 0 to 99 

In the outer loop ,we will take the first element position as m=0;, then inner loop simply checks one by one which is largest and saves its position as m . and apply reverse from i to m i.e from 0 to m ,which will bring the largest element in the first position and the remaining array elements will be in random order.

Now we will apply the  2nd iteration from i=1 ,put m=1; and repeat the above step which will bring the largest element from remaining array to i=1 position ,hence it is just like sorted the array in descending order

Answer 3