public tuple insertItem(tuple newData) // O(log k) time
{
int index;
tuple pointer;
if (heaplimit >= (arraysize - 1))
{
grow();
} // if heap is full, grow by factor of 2
index = heaplimit; //
A[index].d.m = newData.m; // copy newData onto the bottom of the heap
A[index].d.i = newData.i; //
A[index].d.j = newData.j; //
A[index].d.k = index;
A[index].d.enabled = true;
pointer = A[index].d; // store pointer to container
pointer.enabled = true;
heaplimit++; // note the larger heap
upsift(index); // upsift new item up to proper spot
if (heaplimit > 1)
{
isempty = false;
}
return(pointer);
}
public tuple popMaximum() // removes and returns heap max, reheapifies
{ // O(log k) time
tuple temp = returnMaximum();
deleteItem(A[1].d);
return(temp);
}
public void shrink() // decrease size of array A
{ // O(k) time
tuple newtuple;
hnode[] B; // scratch space for contraction of A
B = new hnode [heaplimit]; //
for (int i = 0; i < heaplimit; i++)
{
B[i].d = A[i].d;
} // copy A into B
// delete old array of addresses
A = new hnode [arraysize / 2]; // shrink A by factor of 2
for (int i = 0; i < heaplimit; i++)
{
A[i].d = B[i].d;
} // copy B into A
for (int i = heaplimit; i < (arraysize / 2); i++) // initialize new heap values
{
newtuple = new tuple(); //
A[i].d = newtuple; //
A[i].d.m = -4294967296.0; //
A[i].d.i = 0; //
A[i].d.j = 0; //
A[i].d.k = i; //
}
// delete scratch space B
arraysize = arraysize / 2; // update size of array
return;
}
public void grow() //increase size of array A
{
tuple newtuple;
hnode[] B; // scratch space for expansion of A
B = new hnode [arraysize]; //
for (int i = 0; i < arraysize; i++)
{
B[i].d = A[i].d;
} // copy A into B
// delete old array of addresses
A = new hnode [2 * arraysize]; // grow A by factor of 2
for (int i = 0; i < arraysize; i++)
{
A[i].d = B[i].d;
} // copy B into first half of A
for (int i = arraysize; i < (2 * arraysize); i++) // initialize new heap values
{
newtuple = new tuple(); //
A[i].d = newtuple; //
A[i].d.m = -4294967296.0; //
A[i].d.i = 0; //
A[i].d.j = 0; //
A[i].d.k = i; //
}
// delete scratch space B
arraysize = 2 * arraysize; // update size of array
return;
}
public void updateItemdub(tuple address, double newStored) // O(log k) time
{
double oldm = address.m;
address.m = newStored; // udpate the dQ stored
if (oldm > newStored)
{
downsift(address.k);
} // downsift if old value was larger
else
{
upsift(address.k);
} // upsift otherwise
return;
}
public void updateItem(tuple address, tuple newData) // O(log k) time
{
double oldm = address.m;
address.m = newData.m; // udpate the dQ stored
address.j = newData.j; // udpate the community to which to join
if (oldm > newData.m)
{
downsift(address.k);
} // downsift if old value was larger
else
{
upsift(address.k);
} // upsift otherwise
return;
}
public modmaxheap(int size) // default constructor
{
tuple newtuple;
heaplimit = 1; // first free location is A[1]
arraysize = size + 1; //
isempty = true; // heap is initially empty
A = new hnode [arraysize]; // allocate array for heap
for (int i = 0; i < arraysize; i++) // initialize heap values
{
newtuple = new tuple(); //
A[i].d = newtuple; //
A[i].d.m = -4294967296.0; // a very negative value; unlikely to be a valid dQ
A[i].d.i = 0; //
A[i].d.j = 0; //
A[i].d.k = i; //
}
}
public void deleteItem(tuple address)
{
tuple swap;
int small = heaplimit - 1;
int index = address.k;
if (heaplimit == 2) // check if deleting last item in heap
{
A[1].d.m = -4294967296.0; // zero out root data
A[1].d.i = 0; //
A[1].d.j = 0; //
A[1].d.k = 1; //
A[1].d.enabled = false;
isempty = true; // note the heap's emptiness
heaplimit--; // decrement size of heap to empty
}
else
{
if (index >= A.Length)
{
grow();
}
A[index].d.m = -4294967296.0; // zero out the deleted item's data
A[index].d.i = 0; //
A[index].d.j = 0;
A[index].d.enabled = false;
swap = A[index].d; // swap this element with item at end of heap
A[index].d = A[small].d; //
A[small].d = swap; //
A[index].d.k = index; // note the change in locations
A[small].d.k = small; //
heaplimit--; // note change in heap size
downsift(index); // downsift moved element to new location; O(log k)
if ((heaplimit / 2 > heapmin) && (heaplimit == (arraysize / 2)))
{
shrink();
} // shrink by factor of 2 if necessary
}
return;
}
