b树

B树的构造

// a binary tree
// node, two child nodes(left, right)
// nodes with children are parent node.
// child nodes may contain references to their parents.

package main

import (
	"fmt"
	"io"
	"log"
)

type BinaryNode struct {
	left  *BinaryNode
	right *BinaryNode
	data  int64
}

type BinaryTree struct {
	root *BinaryNode
}

type d struct {
}

func (d) Write(p []byte) (int, error) {
	log.Println("----------", string(p))
	return 0, nil
}

func (t *BinaryTree) insert(data int64) *BinaryTree {
	if t.root == nil {
		t.root = &BinaryNode{data: data, left: nil, right: nil}
	} else {
		t.root.insert(data)
	}
	return t
}

func (n *BinaryNode) insert(data int64) {
	if n == nil {
		return
	} else if data <= n.data {
		if n.left == nil {
			n.left = &BinaryNode{data: data, left: nil, right: nil}
		} else {
			n.left.insert(data)
		}
	} else {
		if n.right == nil {
			n.right = &BinaryNode{data: data, left: nil, right: nil}
		} else {
			n.right.insert(data)
		}
	}
}

func print(w io.Writer, node *BinaryNode, ns int, ch rune) {
	if node == nil {
		return
	}
	for i := 0; i < ns; i++ {
		// fmt.Print(w, " ")
	}
	fmt.Fprintf(w, "%c:%v
", ch, node.data)
	print(w, node.left, ns+2, 'L')
	print(w, node.right, ns+2, 'R')
}

func main() {
	tree := &BinaryTree{}
	tree.insert(100).
		insert(-20).
		insert(90).
		insert(80).
		insert(-50)
	var dins d = d{}
	print(dins, tree.root, 0, 'M')
}