package main

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

func dfs(t *tree.Tree, ch chan int) {
    if (t == nil) { return }

    dfs(t.Left, ch)
    ch <- t.Value
    dfs(t.Right, ch)
}

func Walk(t *tree.Tree, ch chan int) {
    dfs(t, ch)
    close(ch)
}

func Same(t1, t2 *tree.Tree) bool {
    ch1 := make(chan int)
    ch2 := make(chan int)
    go Walk(t1, ch1)
    go Walk(t2, ch2)

    var f func(ch1 chan int, ch2 chan int) bool
    f = func(ch1 chan int, ch2 chan int) bool {
        v1, ok1 := <-ch1
        v2, ok2 := <-ch2

        if (!ok1 || !ok2) {
            return ok1 == ok2
        }
        return v1 == v2 && f(ch1, ch2)
    }

    return f(ch1, ch2)
}

func main() {
    t1 := tree.New(1)
    t2 := tree.New(1)
    fmt.Println(Same(t1, t2))
}