Equivalent binary trees in Go Solution to http://tour.golang.org/#70

equi.go

// Copyright 2011 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"fmt"
	"math/rand"
)

// A Tree is a binary tree with integer values.
type Tree struct {
	Left  *Tree
	Value int
	Right *Tree
}

// New returns a new, random binary tree holding the values k, 2k, ..., 10k.
func New(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 (t *Tree) Walk() string {
	s := ""
	if t.Left != nil {
		s += t.Left.Walk()
	}
	s += fmt.Sprintf("%d", t.Value)

	if t.Right != nil {
		s += t.Right.Walk()
	}
	return s
}

func (t *Tree) WalkChan(c chan string) {
	s := t.Walk()
	c <- s
}

func Same(t1, t2 *Tree) bool {
	c := make(chan string)
	go t1.WalkChan(c)
	go t2.WalkChan(c)

	one, two := <-c, <-c
	return one == two
}

func main() {

	one := New(100)
	two := New(100)

	three := New(100)
	four := New(200)

	fmt.Println(Same(three, four))
	fmt.Println(Same(one, two))

}