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/* btree.cpp
* Date: 2021-11-22
* Author: Aryadev Chavali
*/
#include <iostream>
enum Order
{
LT,
GT,
EQ
};
template <typename T>
struct BinaryTree
{
T value;
BinaryTree<T> *left, *right;
BinaryTree(T val, BinaryTree<T> *l, BinaryTree<T> *r)
{
value = val;
left = l;
right = r;
}
~BinaryTree()
{
delete left;
delete right;
}
};
template <typename T>
using comp_fn = enum Order (*)(T, T);
template <typename T>
BinaryTree<T> *insert(BinaryTree<T> *tree, T value, comp_fn<T> compare)
{
BinaryTree<T> **node = &tree;
switch (compare(value, tree->value))
{
case LT:
node = &tree->left;
break;
case EQ:
case GT:
node = &tree->right;
break;
}
*node = *node ? insert(*node, value, compare)
: new BinaryTree<T>(value, nullptr, nullptr);
return tree;
}
template <typename T>
void rightRotate(BinaryTree<T> **tree)
{
auto left = *tree->left;
*tree->left = left->right;
left->right = *tree;
*tree = left;
}
template <typename T>
void leftRotate(BinaryTree<T> **tree)
{
auto right = (*tree)->right;
(*tree)->right = right->left;
right->left = *tree;
*tree = right;
}
template <typename T>
std::ostream &operator<<(std::ostream &ostream, const BinaryTree<T> *btree)
{
if (!btree)
return ostream;
ostream << "(" << btree->value;
if (btree->left)
ostream << " " << btree->left;
if (btree->right)
ostream << " " << btree->right;
ostream << ")";
return ostream;
}
int main(void)
{
comp_fn<int> cmp = [](int x, int y)
{
if (x < y)
return LT;
else if (x > y)
return GT;
else
return EQ;
};
auto tree = new BinaryTree<int>(5, NULL, NULL);
for (int i = 0; i <= 5; ++i)
tree = insert(tree, i * 2, cmp);
std::cout << tree << std::endl;
leftRotate(&tree);
std::cout << tree << std::endl;
delete tree;
return 0;
}
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