http://go-tour-jp.appspot.com/#70

go-tour-70.go

package main

import "code.google.com/p/go-tour/tree"

import (
	"fmt"
)

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

// Walk walks the tree t sending all values
// from the tree to the channel ch.
func Walk(t *tree.Tree, ch chan int) {

	walk := func(t *tree.Tree) {}
	walk = func(t *tree.Tree) {
		if t != nil {
			walk(t.Left)
			ch <- t.Value
			walk(t.Right)
		}
	}

	walk(t)

	close(ch)
}

// Same determines whether the trees
// t1 and t2 contain the same values.
func Same(t1, t2 *tree.Tree) bool {
	ch1 := make(chan int)
	ch2 := make(chan int)

	go Walk(t1, ch1)
	go Walk(t2, ch2)
    /*
	for v1 := range ch1 {
		if v1 != <-ch2 {
			return false
		}
	}
	*/
	for {
		v1, ok1 := <-ch1
		v2, ok2 := <-ch2

		if v1 != v2 {
			return false
		}

		if !ok1 && !ok2 {
			break
		}
	}

	return true
}

func main() {
	ch := make(chan int)
	t := tree.New(1)

	go Walk(t, ch)

	for v := range ch {
		fmt.Print(v, " ")
	}
	fmt.Println("")

	fmt.Println(Same(tree.New(1), tree.New(1)))
	fmt.Println(Same(tree.New(1), tree.New(2)))
}