https://tour.golang.org/concurrency/8

exercise-equivalent-binary-trees.go

package main

import "golang.org/x/tour/tree"
import "fmt"

func walk(t *tree.Tree, ch chan int) {
	if t == nil {
		return
	}
	walk(t.Left, ch)
	ch<-t.Value
	walk(t.Right, ch)
}

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

// Same determines whether the trees
// t1 and t2 contain the same values.
func Same(t1, t2 *tree.Tree) bool {
	ch1, ch2 := make(chan int), make(chan int)
	
	go Walk(t1, ch1)
	go Walk(t2, ch2)
	
	for {
		x, xok := <-ch1
		y, yok := <-ch2
		if x != y || xok != yok {
			return false
		} else if !xok {
			return true
		}
	}
}

func main() {
	ch := make(chan int)
	go Walk(tree.New(1), ch)
	for i := 0; i < 10; i++ {
		fmt.Println(<-ch)
	}
	
	fmt.Println(Same(tree.New(1), tree.New(1)), "should be true")
	fmt.Println(Same(tree.New(1), tree.New(2)), "should be false")
}