Merging two sorted linkedLists

Problem statement: Merging a sorted lists to a single

// Here is a simplex LinkedList
class simplelinkedist
{
public int value;
public simplelinkedist next = null;
public simplelinkedist(int v)
{
value = v;
}
}

simplelinkedist temp = null;
simplelinkedist listone = new simplelinkedist(0);
simplelinkedist listtwo = new simplelinkedist(1);

// Fill the first one with even numbers
temp = listone;
for (int i = 2; i < 12; i = i + 2)
{
temp.next = new simplelinkedist(i);
temp = temp.next;
}
// Fill the second one with ODD numberss
temp = listtwo;
for (int i = 3; i < 13; i = i + 2)
{
temp.next = new simplelinkedist(i);
temp = temp.next;
}

// Display the first one
temp = listone;
label1.Text = "";
while (temp!= null)
{
label1.Text += temp.value.ToString() + "\n\r";
temp = temp.next;
}

// Display the second one
temp = listtwo;
label2.Text = "";
while (temp != null)
{
label2.Text += temp.value.ToString() + "\n\r";
temp = temp.next;
}



//Merge them and show
simplelinkedist mergedone = mergetheLists(listone, listtwo);

// Display them
temp = mergedone;
label3.Text = "";
while (temp != null)
{
label3.Text += temp.value.ToString() + "\n\r";
temp = temp.next;
}

// Here goes the Merging Function
private simplelinkedist mergetheLists(simplelinkedist a, simplelinkedist b )
{
if ((a == null) && (b == null))
{
return null;
}
simplelinkedist myanswer = null;
if(b==null)
{
myanswer = a;
myanswer.next = mergetheLists(a.next, null);
}
else if (a == null)
{
myanswer = b;
myanswer.next = mergetheLists(null, b.next);
}
else
{

if (a.value < b.value)
{
myanswer = a;
myanswer.next = mergetheLists(a.next, b);
}
else
{
myanswer = b;
myanswer.next = mergetheLists(a, b.next);
}

}
return myanswer;
}

Assumptions: This methods Think that the given arrays are sorted in ASC order.

I prefer to add the code for desc order too....
In any case caller has to pass right boolean (asc/desc) and right Linked lists :)

So
//Merge them and show
simplelinkedist mergedone = mergetheLists(listone, listtwo,true);

private simplelinkedist mergetheLists(simplelinkedist a, simplelinkedist b ,bool asc)
{
if ((a == null) && (b == null))
{
return null;
}
simplelinkedist myanswer = null;
if(b==null)
{
myanswer = a;
myanswer.next = mergetheLists(a.next, null,asc);
}
else if (a == null)
{
myanswer = b;
myanswer.next = mergetheLists(null, b.next,asc);
}
else
{
if (asc)
{

if (a.value < b.value)
{
myanswer = a;
myanswer.next = mergetheLists(a.next, b, asc);
}
else
{
myanswer = b;
myanswer.next = mergetheLists(a, b.next, asc);
}
}
else
{
if (a.value > b.value)
{
myanswer = a;
myanswer.next = mergetheLists(a.next, b, asc);
}
else
{
myanswer = b;
myanswer.next = mergetheLists(a, b.next, asc);
}
}

}
return myanswer;
}

Can we do it non recursively and for two sorted arrays of integers?

for some reason I don't like using recursion
mostly memory usage is a big concern


merging two sorted "arrays" is the problemstatement.
But the code uses linkedlist.

If code is using singly linked list, is it checking for loops in it?

Little more help to the processor would be with thefollowing changes

private void sweepneighbours(int iii, int jjj,bool diag )
{
if ((iii < width) && (jjj < height))
{
//sweep self
if (((int)TwoDimArray.GetValue(iii, jjj)) != 0)
{
// This is an important step -- otherwise we will endup recusive call for neighbours
MyOwnArray.SetValue(true, iii, jjj);


//sweep top left
if ( diag&& ((iii - 1) > -1) &&
((jjj - 1) > -1) &&
((bool)MyOwnArray.GetValue(iii - 1, jjj - 1) == false ) )
{
if (((int)TwoDimArray.GetValue(iii - 1, jjj - 1)) != 0)
{
sweepneighbours(iii - 1, jjj - 1, diag);
}
else
{
MyOwnArray.SetValue(true, iii - 1, jjj - 1);
}
}

//sweep top == Already done
if ( ((jjj - 1) > -1) &&
((bool)MyOwnArray.GetValue(iii, jjj - 1) == false) )
{
if (((int)TwoDimArray.GetValue(iii, jjj - 1)) != 0)
{
sweepneighbours(iii, jjj - 1, diag);
}
else
MyOwnArray.SetValue(true, iii, jjj - 1);
}

//sweep topright == Already done
if ( diag&& ((iii + 1) < width) &&
((jjj - 1) > -1) &&
((bool)MyOwnArray.GetValue(iii+1, jjj - 1) == false) )
{
if (((int)TwoDimArray.GetValue(iii + 1, jjj - 1)) != 0)
{
sweepneighbours(iii + 1, jjj - 1, diag);
}
else
MyOwnArray.SetValue(true, iii + 1, jjj - 1);
}
//sweep left == Already done
if ( ((iii - 1) > -1) &&
((bool)MyOwnArray.GetValue(iii - 1, jjj) == false) )
{
if (((int)TwoDimArray.GetValue(iii - 1, jjj)) != 0)
{
sweepneighbours(iii - 1, jjj, diag);
}
else
MyOwnArray.SetValue(true, iii - 1, jjj);
}
//sweep right
if ( ((iii + 1) < width) &&
((bool)MyOwnArray.GetValue(iii + 1, jjj) == false) )
{
if (((int)TwoDimArray.GetValue(iii + 1, jjj)) != 0)
{
sweepneighbours(iii + 1, jjj, diag);
}
else
MyOwnArray.SetValue(true, iii + 1, jjj);
}
//sweep bottomleft
if ( diag&& ((iii - 1) > -1) &&
((jjj + 1) < height) &&
((bool)MyOwnArray.GetValue(iii - 1, jjj + 1) == false) )
{
if (((int)TwoDimArray.GetValue(iii - 1, jjj + 1)) != 0)
{
sweepneighbours(iii - 1, jjj + 1, diag);
}
else
MyOwnArray.SetValue(true, iii - 1, jjj + 1);
}
//sweep bottom
if ( ((jjj + 1) < width) &&
((bool)MyOwnArray.GetValue(iii, jjj + 1) == false) )
{
if (((int)TwoDimArray.GetValue(iii, jjj + 1)) != 0)
{
sweepneighbours(iii, jjj + 1, diag);
}
else
MyOwnArray.SetValue(true, iii, jjj + 1);
}
//sweep bottom right
if ( diag&& ((iii + 1) < width) &&
((jjj + 1) < height) &&
((bool)MyOwnArray.GetValue(iii + 1 , jjj + 1) == false) )
{
if (((int)TwoDimArray.GetValue(iii + 1, jjj + 1)) != 0)
{
sweepneighbours(iii + 1, jjj + 1, diag);
}
else
MyOwnArray.SetValue(true, iii + 1, jjj + 1);

}
}
}
}