static int insert_int(BiTree *tree, int i) {
BiTreeNode *node,
*prev;
int direction,
*data;
/*****************************************************************************
* *
* Insert i assuming a binary tree organized as a binary search tree. *
* *
*****************************************************************************/
node = tree->root;
direction = 0;
while (!bitree_is_eob(node)) {
prev = node;
if (i == *(int *)bitree_data(node)) {
return -1;
}
else if (i < *(int *)bitree_data(node)) {
node = bitree_left(node);
direction = 1;
}
else {
node = bitree_right(node);
direction = 2;
}
}
if ((data = (int *)malloc(sizeof(int))) == NULL)
return -1;
*data = i;
if (direction == 0)
return bitree_ins_left(tree, NULL, data);
if (direction == 1)
return bitree_ins_left(tree, prev, data);
if (direction == 2)
return bitree_ins_right(tree, prev, data);
return -1;
}
int bitree_merge(BiTree *merge, BiTree *left, BiTree *right, const void
*data) {
/*****************************************************************************
* *
* Initialize the merged tree. *
* *
*****************************************************************************/
bitree_init(merge, left->destroy);
/*****************************************************************************
* *
* Insert the data for the root node of the merged tree. *
* *
*****************************************************************************/
if (bitree_ins_left(merge, NULL, data) != 0) {
bitree_destroy(merge);
return -1;
}
/*****************************************************************************
* *
* Merge the two binary trees into a single binary tree. *
* *
*****************************************************************************/
bitree_root(merge)->left = bitree_root(left);
bitree_root(merge)->right = bitree_root(right);
/*****************************************************************************
* *
* Adjust the size of the new binary tree. *
* *
*****************************************************************************/
merge->size = merge->size + bitree_size(left) + bitree_size(right);
/*****************************************************************************
* *
* Do not let the original trees access the merged nodes. *
* *
*****************************************************************************/
left->root = NULL;
left->size = 0;
right->root = NULL;
right->size = 0;
return 0;
}
int main(void) {
BiTree * tree;
char * a[] = {"kobe", "bryant", "james", "jordan", "johnson"};
List *list;
ListNode *node;
tree = (BiTree *) malloc(sizeof(BiTree));
if (tree == NULL) return -1;
list = (List *) malloc(sizeof(List));
if (list == NULL) return -1;
bitree_init(tree, &data_destroy);
bitree_ins_left(tree, NULL, a[0]);
bitree_ins_left(tree, tree->root, a[1]);
bitree_ins_right(tree, tree->root, a[2]);
bitree_ins_left(tree, tree->root->left, a[3]);
bitree_ins_right(tree, tree->root->left, a[4]);
//list init
list_init(list, &data_destroy);
postorder(tree->root, list);
node = list->head;
while(node != NULL) {
printf("%s\n", (char *) node->data );
node = node->next;
}
bitree_destroy(tree);
list_destroy(list);
return 0;
}
int main(int argc, char const *argv[])
{
//create a unbalanced tree
BiTree * unbalanced_tree = (BiTree*)malloc(sizeof(BiTree));
bitree_init(unbalanced_tree, NULL);
int tree_node_index[5];
for (int i = 0; i < 5; ++i)
{
tree_node_index[i] = i;
}
BiTreeNode * position = NULL;
bitree_ins_left(unbalanced_tree, NULL, (void *)&tree_node_index[0]);
bitree_ins_left(unbalanced_tree, bitree_root(unbalanced_tree), (void *)&tree_node_index[1]);
position = bitree_root(unbalanced_tree)->left;
bitree_ins_left(unbalanced_tree, position, (void *)&tree_node_index[2]);
position = position->left;
bitree_ins_left(unbalanced_tree, position, (void *)&tree_node_index[3]);
bitree_ins_right(unbalanced_tree, bitree_root(unbalanced_tree), (void *)&tree_node_index[4]);
int balance_check_result = check_balance(bitree_root(unbalanced_tree));
if(balance_check_result < 0)
printf("unbalanced tree\n");
else
printf("balanced tree\n");
bitree_destroy(unbalanced_tree);
free(unbalanced_tree);
//create a balanced tree
BiTree * balanced_tree = (BiTree *)malloc(sizeof(BiTree));
bitree_init(balanced_tree, NULL);
bitree_ins_left(balanced_tree, NULL, (void *)&tree_node_index[0]);
bitree_ins_left(balanced_tree, bitree_root(balanced_tree), (void *)&tree_node_index[1]);
position = bitree_root(balanced_tree)->left;
bitree_ins_left(balanced_tree, position, (void *)&tree_node_index[2]);
bitree_ins_right(balanced_tree, position, (void *)&tree_node_index[3]);
bitree_ins_right(balanced_tree, bitree_root(balanced_tree), (void *)&tree_node_index[4]);
balance_check_result = check_balance(bitree_root(balanced_tree));
if(balance_check_result < 1)
printf("unbalanced!\n");
else
printf("balanced\n");
bitree_destroy(balanced_tree);
free(balanced_tree);
return 0;
}
struct bitree *build(int n)
{
int i, *data;
struct bitree *tree = NULL;
struct bitree_node *position = NULL;
tree = (struct bitree *) malloc(sizeof(struct bitree));
if (!tree)
return NULL;
bitree_init(tree, NULL);
data = (int *) malloc(n * sizeof(int));
if (!data) {
goto fail;
}
for (i = 0; i <= n/2; i++) {
data[i] = i + 1;
if (bitree_ins_left(tree, position, (const void *) &data[i]) != 0)
goto fail;
if (!position) {
if (bitree_root(tree) == NULL)
goto fail;
position = bitree_root(tree);
} else {
position = position->left;
}
}
position = bitree_root(tree);
for (i = n/2 + 1; i < n; i++) {
data[i] = i + 1;
if (bitree_ins_right(tree, position, (const void *) &data[i]) != 0)
goto fail;
position = position->right;
}
return tree;
fail:
free(tree);
return NULL;
}
static int build_tree(int *freqs, BiTree **tree) {
BiTree *init,
*merge,
*left,
*right;
PQueue pqueue;
HuffNode *data;
int size,
c;
/*****************************************************************************
* *
* Initialize the priority queue of binary trees. *
* *
*****************************************************************************/
*tree = NULL;
pqueue_init(&pqueue, compare_freq, destroy_tree);
for (c = 0; c <= UCHAR_MAX; c++) {
if (freqs[c] != 0) {
/***********************************************************************
* *
* Set up a binary tree for the current symbol and its frequency. *
* *
***********************************************************************/
if ((init = (BiTree *)malloc(sizeof(BiTree))) == NULL) {
pqueue_destroy(&pqueue);
return -1;
}
bitree_init(init, free);
if ((data = (HuffNode *)malloc(sizeof(HuffNode))) == NULL) {
pqueue_destroy(&pqueue);
return -1;
}
data->symbol = c;
data->freq = freqs[c];
if (bitree_ins_left(init, NULL, data) != 0) {
free(data);
bitree_destroy(init);
free(init);
pqueue_destroy(&pqueue);
return -1;
}
/***********************************************************************
* *
* Insert the binary tree into the priority queue. *
* *
***********************************************************************/
if (pqueue_insert(&pqueue, init) != 0) {
bitree_destroy(init);
free(init);
pqueue_destroy(&pqueue);
return -1;
}
}
}
/*****************************************************************************
* *
* Build a Huffman tree by merging trees in the priority queue. *
* *
*****************************************************************************/
size = pqueue_size(&pqueue);
for (c = 1; c <= size - 1; c++) {
/**************************************************************************
* *
* Allocate storage for the next merged tree. *
* *
**************************************************************************/
if ((merge = (BiTree *)malloc(sizeof(BiTree))) == NULL) {
pqueue_destroy(&pqueue);
return -1;
}
/**************************************************************************
* *
* Extract the two trees whose root nodes have the smallest frequencies. *
* *
**************************************************************************/
if (pqueue_extract(&pqueue, (void **)&left) != 0) {
pqueue_destroy(&pqueue);
free(merge);
return -1;
}
if (pqueue_extract(&pqueue, (void **)&right) != 0) {
pqueue_destroy(&pqueue);
free(merge);
return -1;
}
/**************************************************************************
* *
* Allocate storage for the data in the root node of the merged tree. *
* *
**************************************************************************/
if ((data = (HuffNode *)malloc(sizeof(HuffNode))) == NULL) {
pqueue_destroy(&pqueue);
free(merge);
return -1;
}
memset(data, 0, sizeof(HuffNode));
/**************************************************************************
* *
* Sum the frequencies in the root nodes of the trees being merged. *
* *
**************************************************************************/
data->freq = ((HuffNode *)bitree_data(bitree_root(left)))->freq +
((HuffNode *)bitree_data(bitree_root(right)))->freq;
/**************************************************************************
* *
* Merge the two trees. *
* *
**************************************************************************/
if (bitree_merge(merge, left, right, data) != 0) {
pqueue_destroy(&pqueue);
free(merge);
return -1;
}
/**************************************************************************
* *
* Insert the merged tree into the priority queue and free the others. *
* *
**************************************************************************/
if (pqueue_insert(&pqueue, merge) != 0) {
pqueue_destroy(&pqueue);
bitree_destroy(merge);
free(merge);
return -1;
}
free(left);
free(right);
}
/*****************************************************************************
* *
* The last tree in the priority queue is the Huffman tree. *
* *
*****************************************************************************/
if (pqueue_extract(&pqueue, (void **)tree) != 0) {
pqueue_destroy(&pqueue);
return -1;
}
else {
pqueue_destroy(&pqueue);
}
return 0;
}
static int
insert (BisTree *tree, BiTreeNode **node, const void *data, int *balanced)
{
AvlNode *avl_data;
int cmpval, retval;
/* Insert the data into the tree. */
if (bitree_is_eob (*node))
{
/* Handle insertion into an empty tree. */
if ((avl_data = (AvlNode *) malloc (sizeof(AvlNode))) == NULL)
return -1;
avl_data->factor = AVL_BALANCED;
avl_data->hidden = 0;
avl_data->data = (void *) data;
return bitree_ins_left (tree, *node, avl_data);
}
else
{
/* Handle insertion into a tree that is not empty. */
cmpval = tree->compare (data, ((AvlNode *) bitree_data (*node))->data);
if (cmpval < 0)
{
/* Move to the left. */
if (bitree_is_eob (bitree_left (*node)))
{
if ((avl_data = (AvlNode *) malloc (sizeof(AvlNode))) == NULL)
return -1;
avl_data->factor = AVL_BALANCED;
avl_data->hidden = 0;
avl_data->data = (void *) data;
if (bitree_ins_left (tree, *node, avl_data) != 0)
return -1;
*balanced = 0;
}
else
{
if ((retval = insert(tree, &bitree_left(*node), data, balanced)) != 0)
{
return retval;
}
}
/* Ensure that the tree remains balanced. */
if (!(*balanced))
{
switch (((AvlNode *) bitree_data (*node))->factor)
{
case AVL_LFT_HEAVY:
rotate_left (node);
*balanced = 1;
break;
case AVL_BALANCED:
((AvlNode *) bitree_data (*node))->factor = AVL_LFT_HEAVY;
break;
case AVL_RGT_HEAVY:
((AvlNode *) bitree_data (*node))->factor = AVL_BALANCED;
*balanced = 1;
}
}
} /* if (cmpval < 0) */
else if (cmpval > 0)
{
/* Move to the right. */
if (bitree_is_eob (bitree_right (*node)))
{
if ((avl_data = (AvlNode *) malloc (sizeof(AvlNode))) == NULL)
return -1;
avl_data->factor = AVL_BALANCED;
avl_data->hidden = 0;
avl_data->data = (void *) data;
if (bitree_ins_right (tree, *node, avl_data) != 0)
return -1;
*balanced = 0;
}
else
{
if ((retval = insert (tree, &bitree_right (*node), data, balanced)) != 0)
{
return retval;
}
}
/* Ensure that the tree remains balanced. */
if (!(*balanced))
{
switch (((AvlNode *) bitree_data (*node))->factor)
{
case AVL_LFT_HEAVY:
((AvlNode *) bitree_data (*node))->factor = AVL_BALANCED;
*balanced = 1;
break;
case AVL_BALANCED:
((AvlNode *) bitree_data (*node))->factor = AVL_RGT_HEAVY;
break;
case AVL_RGT_HEAVY:
rotate_right (node);
*balanced = 1;
}
}
} /* if (cmpval > 0) */
else
{
/* Handle finding a copy of the data. */
if (!((AvlNode *) bitree_data (*node))->hidden)
{
/* Do nothing since the data is in the tree and not hidden. */
return 1;
}
else
{
/* Insert the new data and mark it as not hidden. */
if (tree->destroy != NULL)
{
/* Destroy the hidden data since it is being replaced. */
tree->destroy (((AvlNode *) bitree_data (*node))->data);
}
((AvlNode *) bitree_data (*node))->data = (void *) data;
((AvlNode *) bitree_data (*node))->hidden = 0;
/* Do not rebalance because the tree structure is unchanged. */
*balanced = 1;
}
}
}
return 0;
}
