Convert sorted arrays to balanced BSTs

array_to_tree.go

// xkool 22.06.18
package main

import "fmt"

type Node struct {
	Data        int
	Left, Right *Node
}

func arrayToTree(arr []int, start, end int) (n *Node) {
	if start > end {
		return
	}
	middle := (start + end) / 2
	n = &Node{Data: arr[middle]}
	n.Left = arrayToTree(arr, start, middle-1)
	n.Right = arrayToTree(arr, middle+1, end)
	return
}

func printPreorder(n *Node) {
	if n == nil {
		return
	}
	fmt.Println(n.Data)
	printPreorder(n.Left)
	printPreorder(n.Right)
}

func main() {
	input := []int{1, 2, 3, 4, 5, 6, 7}
	root := arrayToTree(input, 0, len(input)-1)
	printPreorder(root)
}