Algorithm-Red black tree rotation

(citation) https://studygolang.com/articles/7014

The rotation of the tree includes the left and right spins, illustrated below

Left-hand: with P as the pivot, n the original parent node p as the left child of the N-node, the left child of the original N-node becomes the right child of P-node, which is completed.

Right: Similar to the left hand, just the right child of the N node becomes the child of the P node.

A few notes are required:

1. The left side of the node must have a right child, right-handed must have left child.
2. If n is rotated into a root node, it is important to remember to point root pointer root in the rbtree struct to N, which is an error-prone place.

Algorithm-Red black tree rotation