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A red-black tree is a binary search tree with the following properties: Every node is colored with either red or black. All leaf (nil) nodes are colored with black; if a node's child is missing then we will assume that it has a nil child in that place and this nil child is always colored black.
Rules That Every Red-Black Tree Follows:The root of the tree is always black. There are no two adjacent red nodes (A red node cannot have a red parent or red child). Every path from a node (including root) to any of its descendants NULL nodes has the same number of black nodes. All leaf nodes are black nodes.
Red-black trees are a fairly simple and very efficient data structure for maintaining a balanced binary tree. The idea is to strengthen the representation invariant so a tree has height logarithmic in n. To help enforce the invariant, we color each node of the tree either red or black.
Properties of a red-black tree Each tree node is colored either red or black. The root node of the tree is always black. Every path from the root to any of the leaf nodes must have the same number of black nodes. No two red nodes can be adjacent, i.e., a red node cannot be the parent or the child of another red node.
There are lots of questions around about red-black trees but none of them answer how they work. Why is it called red-black? How does this keep the tree balanced (thus increasing performance over an unbalanced normal binary search tree)? I'm just looking for an overview of how and why it works.
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