C - Binary trees

0. New node

Write a function that creates a binary tree node

Prototype: binary_tree_t *binary_tree_node(binary_tree_t *parent, int value);
Where parent is a pointer to the parent node of the node to create
And value is the value to put in the new node
When created, a node does not have any child
Your function must return a pointer to the new node, or NULL on failure

1. Insert left

Write a function that inserts a node as the left-child of another node

Prototype: binary_tree_t *binary_tree_insert_left(binary_tree_t *parent, int value);
Where parent is a pointer to the node to insert the left-child in
And value is the value to store in the new node
Your function must return a pointer to the created node, or NULL on failure or if parent is NULL
If parent already has a left-child, the new node must take its place, and the old left-child must be set as the left-child of the new node.

2. Insert right

Write a function that inserts a node as the right-child of another node

Prototype: binary_tree_t *binary_tree_insert_right(binary_tree_t *parent, int value);
Where parent is a pointer to the node to insert the right-child in
And value is the value to store in the new node
Your function must return a pointer to the created node, or NULL on failure or if parent is NULL
If parent already has a right-child, the new node must take its place, and the old right-child must be set 

3. Delete

Write a function that deletes an entire binary tree

Prototype: void binary_tree_delete(binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to delete
If tree is NULL, do nothing

4. Is leaf

Write a function that checks if a node is a leaf

Prototype: int binary_tree_is_leaf(const binary_tree_t *node);
Where node is a pointer to the node to check
Your function must return 1 if node is a leaf, otherwise 0
If node is NULL, return 0

5. Is root

Write a function that checks if a given node is a root

Prototype: int binary_tree_is_root(const binary_tree_t *node);
Where node is a pointer to the node to check
Your function must return 1 if node is a root, otherwise 0
If node is NULL, return 0

6. Pre-order traversal

Write a function that goes through a binary tree using pre-order traversal

Prototype: void binary_tree_preorder(const binary_tree_t *tree, void (*func)(int));
Where tree is a pointer to the root node of the tree to traverse
And func is a pointer to a function to call for each node. The value in the node must be passed as a parameter to this function.
If tree or func is NULL, do nothing

7. In-order traversal

Write a function that goes through a binary tree using in-order traversal

Prototype: void binary_tree_inorder(const binary_tree_t *tree, void (*func)(int));
Where tree is a pointer to the root node of the tree to traverse
And func is a pointer to a function to call for each node. The value in the node must be passed as a parameter to this function.
If tree or func is NULL, do nothing

8. Post-order traversal

Write a function that goes through a binary tree using post-order traversal

Prototype: void binary_tree_postorder(const binary_tree_t *tree, void (*func)(int));
Where tree is a pointer to the root node of the tree to traverse
And func is a pointer to a function to call for each node. The value in the node must be passed as a parameter to this function.
If tree or func is NULL, do nothing

9. Height

Write a function that measures the height of a binary tree

Prototype: size_t binary_tree_height(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to measure the height.
If tree is NULL, your function must return 0

10. Depth

Write a function that measures the depth of a node in a binary tree

Prototype: size_t binary_tree_depth(const binary_tree_t *tree);
Where tree is a pointer to the node to measure the depth
If tree is NULL, your function must return 0

11. Size

Write a function that measures the size of a binary tree

Prototype: size_t binary_tree_size(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to measure the size
If tree is NULL, the function must return 0

12. Leaves

Write a function that counts the leaves in a binary tree

Prototype: size_t binary_tree_leaves(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to count the number of leaves
If tree is NULL, the function must return 0
A NULL pointer is not a leaf

13. Nodes

Write a function that counts the nodes with at least 1 child in a binary tree

Prototype: size_t binary_tree_nodes(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to count the number of nodes
If tree is NULL, the function must return 0
A NULL pointer is not a node

14. Balance factor

Write a function that measures the balance factor of a binary tree

Prototype: int binary_tree_balance(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to measure the balance factor
If tree is NULL, return 0

15. Is full mandatory

Write a function that checks if a binary tree is full

Prototype: int binary_tree_is_full(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to check
If tree is NULL, your function must return 0

16. Is perfect mandatory

Write a function that checks if a binary tree is perfect

Prototype: int binary_tree_is_perfect(const binary_tree_t *tree);
Where tree is a pointer to the root node of the tree to check
If tree is NULL, your function must return 0

17. Sibling mandatory

Write a function that finds the sibling of a node

Prototype: binary_tree_t *binary_tree_sibling(binary_tree_t *node);
Where node is a pointer to the node to find the sibling
Your function must return a pointer to the sibling node
If node is NULL or the parent is NULL, return NULL
If node has no sibling, return NULL

18. Uncle mandatory

Write a function that finds the uncle of a node

Prototype: binary_tree_t *binary_tree_uncle(binary_tree_t *node);
Where node is a pointer to the node to find the uncle
Your function must return a pointer to the uncle node
If node is NULL, return NULL
If node has no uncle, return NULL

19. Lowest common ancestor

Write a function that finds the lowest common ancestor of two nodes

Prototype: binary_tree_t *binary_trees_ancestor(const binary_tree_t *first, const binary_tree_t *second);
Where first is a pointer to the first node
And second is a pointer to the second node
Your function must return a pointer to the lowest common ancestor node of the two given nodes
If no common ancestor was found, your function must return NULL