advent-of-code/hacker-rank/tree-preorder-traversal/main.go

package main
import "fmt"
import "os"
import "bufio"
import "strconv"
import "strings"

func main() {
    var length int
    var tree *node
    
    scanner := bufio.NewScanner(os.Stdin)
    for scanner.Scan() {
        if length == 0 {
            length, _ = strconv.Atoi(scanner.Text())
            continue
        }
   
        for i, txt := range strings.Fields(scanner.Text()) {
            if i >= length { break }
            if v, err := strconv.Atoi(txt); err == nil {
                tree = insert(tree, &node{value: v})
            }
        }
    }
    
    fmt.Println(tree)
}

type node struct {
    value int
    left *node
    right *node
}

func insert(root, n *node) *node {
        if root == nil {
            return n
        }
        if root.value > n.value {
            root.left = insert(root.left, n)
            return root
        }
        root.right = insert(root.right, n)
        return root
}

func (n *node) String() string {
    if n == nil { return "" }
        return fmt.Sprintf("%v %v%v", n.value, n.left.String(), n.right.String())

}