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#include "avl_tree.h"
#include <stdio.h>
#include <stdlib.h>
int max(int a, int b) {
return (a > b) ? a : b;
}
int height_of(AVLTree *node) {
return node == NULL ? 0 : node->height;
}
AVLTree *smallest(AVLTree *node) {
AVLTree *current = node;
while (current->left != NULL)
current = current->left;
return current;
}
AVLTree *rotate_right(AVLTree *y) {
AVLTree *x = y->left;
AVLTree *T2 = x->right;
x->right = y;
y->left = T2;
y->height = max(height_of(y->left), height_of(y->right)) + 1;
x->height = max(height_of(x->left), height_of(x->right)) + 1;
return x;
}
AVLTree *rotate_left(AVLTree *x) {
AVLTree *y = x->right;
AVLTree *T2 = y->left;
y->left = x;
x->right = T2;
x->height = max(height_of(x->left), height_of(x->right)) + 1;
y->height = max(height_of(y->left), height_of(y->right)) + 1;
return y;
}
int balance_of(AVLTree *node) {
return (node == NULL) ? 0 : height_of(node->left) - height_of(node->right);
}
AVLTree *avl_tree_initialize(int value) {
AVLTree *node = malloc(sizeof(AVLTree));
node->value = value;
node->left = NULL;
node->right = NULL;
node->height = 1;
return node;
}
int avl_tree_size(AVLTree *tree) {
int total = 0;
if (tree == NULL)
return total;
if (tree->left)
total += avl_tree_size(tree->left);
if (tree->right)
total += avl_tree_size(tree->right);
return total + 1;
}
AVLTree *avl_tree_insert(AVLTree *tree, int value) {
if (tree == NULL)
return avl_tree_initialize(value);
if (value < tree->value)
tree->left = avl_tree_insert(tree->left, value);
else if (value > tree->value)
tree->right = avl_tree_insert(tree->right, value);
else
return tree;
tree->height = 1 + max(height_of(tree->left), height_of(tree->right));
int balance = balance_of(tree);
if (balance > 1 && value < tree->left->value)
return rotate_right(tree);
if (balance < -1 && value > tree->right->value)
return rotate_left(tree);
if (balance > 1 && value > tree->left->value) {
tree->left = rotate_left(tree->left);
return rotate_right(tree);
}
if (balance < -1 && value < tree->right->value) {
tree->right = rotate_right(tree->right);
return rotate_left(tree);
}
return tree;
}
AVLTree *node_delete(AVLTree *root, int value) {
if (root == NULL)
return root;
if (value < root->value)
root->left = node_delete(root->left, value);
else if (value > root->value)
root->right = node_delete(root->right, value);
else {
if ((root->left == NULL) || (root->right == NULL)) {
AVLTree *temp = root->left ? root->left : root->right;
if (temp == NULL) {
temp = root;
root = NULL;
} else {
*root = *temp;
}
free(temp);
} else {
AVLTree *temp = smallest(root->right);
root->value = temp->value;
root->right = node_delete(root->right, temp->value);
}
}
if (root == NULL)
return root;
root->height = 1 + max(height_of(root->left), height_of(root->right));
int balance = balance_of(root);
if (balance > 1 && balance_of(root->left) >= 0)
return rotate_right(root);
if (balance > 1 && balance_of(root->left) < 0) {
root->left = rotate_left(root->left);
return rotate_right(root);
}
if (balance < -1 && balance_of(root->right) <= 0)
return rotate_left(root);
if (balance < -1 && balance_of(root->right) > 0) {
root->right = rotate_right(root->right);
return rotate_left(root);
}
return root;
}
void print_tree(AVLTree *tree, int level) {
for (int i = 0; i < level; i++)
printf(" ");
if (tree) {
printf("(%d)\n", tree->value);
if (!tree->left && !tree->right)
return;
print_tree(tree->left, level + 1);
print_tree(tree->right, level + 1);
}
else {
printf("( )\n");
}
}
void avl_tree_inspect(AVLTree *tree) {
print_tree(tree, 0);
}
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