//---------------------------------------------------------------------------
// arrayToBSTreeHelper
// Recursive helper function. Calls itself on the left and right sides of the
// array once a NodeData object has been located, stored, and inserted into
// a BST.
void BinTree::arrayToBSTreeHelper(NodeData* tempArray[], const Node* current, int low, int high)
{
if (low > high) // terminate
current = NULL;
else
{
int root = (low + high) / 2; // location of data to insert into BST
NodeData* temp;
temp = tempArray[root]; // temp now holds data that is to be removed from array
tempArray[root] = NULL; // empty out tempArray
insert(temp); // insert temp into BST
// call same function on left array
arrayToBSTreeHelper(tempArray, current, low, root - 1);
// call same function on right array
arrayToBSTreeHelper(tempArray, current, root + 1, high);
}
}
BinTree::Node* BinTree::arrayToBSTreeHelper(NodeData* TreeArray[], int low, int high, Node* ¤t)
{
if (low > high) {
return NULL;
} else {
current = new Node; // exception is thrown if memory is not allocated
current->data = TreeArray[(low + high) / 2];
TreeArray[(low + high) / 2] = NULL;
if (low == high) {
current->left = NULL;
current->right = NULL;
return current;
} else {
int mid = (low + high) / 2;
current->right = arrayToBSTreeHelper(TreeArray, mid + 1, high, current->right);
current->left = arrayToBSTreeHelper(TreeArray, low, mid - 1, current->left);
return current;
}
}
}
//---------------------------------------------------------------------------
// arrayToBSTree
// Builds a BST from tempArray. Creates an empty array of size 100 to begin
// with.
void BinTree::arrayToBSTree(NodeData* tempArray[])
{
int high = 0;
int low = 0;
for(int i = 0; i < 100; i++) // how many indexes are empty?
{
if (tempArray[i] != NULL)
high++;
else
tempArray[i] = NULL;
}
// recursive helper function performs the calculations
arrayToBSTreeHelper(tempArray, root, low, high-1);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
// arrayToBSTree: Recreates the a tree based on the array of NodeData
// Pre Conditions: Tree and array are properly inialized
// Post Conditions: Tree is returned
////////////////////////////////////////////////////////////////////////////////////////////////////
void BinTree::arrayToBSTree(NodeData* TreeArray[])
{
int high = getArraySize(TreeArray);
int low = 0;
root = arrayToBSTreeHelper(TreeArray, low, high, root);
}
