tree.go

package main

import (
	"fmt"
	"math/rand"
)

type Tree struct {
	Left  *Tree
	Value int
	Right *Tree
}

// NewTree returns a new, random binary tree holding the values k, 2k, ..., 10k.
func NewTree(k int) *Tree {
	var t *Tree
	for _, v := range rand.Perm(10) {
		t = insert(t, (1+v)*k)
	}
	return t
}

func insert(t *Tree, v int) *Tree {
	if t == nil {
		return &Tree{nil, v, nil}
	}
	if v < t.Value {
		t.Left = insert(t.Left, v)
	} else {
		t.Right = insert(t.Right, v)
	}
	return t
}

func (t *Tree) String() string {
	if t == nil {
		return "()"
	}
	s := ""
	if t.Left != nil {
		s += t.Left.String() + " "
	}
	s += fmt.Sprint(t.Value)
	if t.Right != nil {
		s += " " + t.Right.String()
	}
	return "(" + s + ")"
}

func Walk(t *Tree, ch chan int, n int) {
	if t.Left != nil {
		Walk(t.Left, ch, n)
	}
	ch <- t.Value
	if t.Right != nil {
		Walk(t.Right, ch, n)
	}
}

func Same(t1, t2 *Tree) bool {
	ch1 := make(chan int)
	ch2 := make(chan int)
	
	go func() {
		Walk(t1, ch1, 1)
		close(ch1)
	}()
	go func() {
		Walk(t2, ch2, 2)
		close(ch2)
	}()
	
	for {
		v1, ok1 := <- ch1
		v2, ok2 := <- ch2
		
		if ok1 == false && ok2 == false {
			return true
		}
		if v1 != v2 {
			return false
		}
	}
}

func main() {
	t1 := NewTree(10)
	t2 := NewTree(10)
	
	println(Same(t1, t2))
}