9.1 You are given two sorted arrays, A and B, and A has a large enough buffer at the end to hold B. Write a method to merge B into A in sorted order.

Option 1.

Create an extra big array C.

iterate both A and B.

return C.

O(m + n)

Option 2.

Assume A is big enough.

Iterate A and B starting from end.

Put max value to the end of A.

int[] merge (int[] a, int[] b, int i)
{
  // assume a[x] has value when x <= i;
  // And a.length = b.length + i;
  
  int m = b.length - 1;
  int n = i;
  int k = a.length - 1;
  for ( k >= 0 )
  {
    if (m < 0)
    {
      a[k] = b[n];
      n --;
    }
    else if (n < 0)
    {
      a[k] = a[m];
      m --;    
    } 
    else if (a[m] >= b[n])
    {
      a[k] = a[m];
      m --;
    }
    else
    {
      a[k] = b[n];
      n --;
    }
    k --;
  }
}

CC150 9.1