AVL Trees:
An AVL Tree is a binary search tree in which
1.The heights of the right subtree and left subtree differ by at most 1.
2.The left subtree and right subtree are them selves AVL Trees.
3.A node is said to be
left-high if the left subtree has greater height
right-high if the right subtree has greater height
equl if the heights of left subtree and right subtree are equl.

Red-Black Trees:

A red black tree is a binary search tree where on any path from the root to a leaf is not more than twice as long any other path from the root to a leaf.

A BST is called an RBT if it satisfies the following four properties.
1.Every node is coloured either block or red.
2.Every leaf is black.(Missing node property)
3.If a node is red , then both of its children are black.(Red constraint)
4.Every simple path from a node to a descendent leaf contains the same number of black nodes.(Black constraint)

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