A Tour of Go - Exercise: Equivalent Binary Trees http://tour.golang.org/#70

btrees_eq.go

package main

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


func _walk(t *tree.Tree, ch chan int) {
    if t.Left != nil {
        _walk(t.Left, ch)
    }
    ch <- t.Value
    if t.Right != nil {
        _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 {
    c1 := make(chan int)
    c2 := make(chan int)
    go Walk(t1, c1)
    go Walk(t2, c2)
    for {
        val1, ok1 := <- c1
        val2, ok2 := <- c2
        if !ok1 || !ok2 {  // one of them finished
            if ok1 != ok2 {  // they didn't finished at the same time
                return false
            }
            break
        }
        if val1 != val2 {
            return false
        }
    }
    return true
}


func main() {
    k := 1
    ch := make(chan int)
    tr := tree.New(k)
    go Walk(tr, ch)
    for i:=0; i < 10; i++ {
        fmt.Println(<-ch)
    }

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

package main

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

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

func Same(t1, t2 *tree.Tree) bool {
	// Way 2 :
	//return fmt.Sprintf("%v", *t1) == fmt.Sprintf("%v", *t2)
	
	// Way 1 -- START
	ch1 := make(chan int)
	ch2 := make(chan int)
	
	go Walk(t1, ch1)
	go Walk(t2, ch2)
	
	if <-ch1 != <-ch2 {
		close(ch1)
		close(ch2)
		return false
	}
	return true
	// Way 1 -- END
}

func main() {
	//fmt.Println(Same(tree.New(1), tree.New(1))) // true
	
	t1 := tree.New(1)
	t2 := tree.New(2)
	fmt.Println(t1, "\n", t2)
	fmt.Println(Same(t1, t2)) // false
}