Exercise: Equivalent Binary Trees (https://tour.golang.org/concurrency/8)

exercise-equivalent-binary-trees.go

package main

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

// Walk walks the tree t sending all values
// from the tree to the channel ch.
func Walk(t *tree.Tree, ch chan int) {
    var walk func(t *tree.Tree)
    walk = func(t * tree.Tree) {
        if t == nil { return }
        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 {
        v2, ok := <- ch2
        if !ok || v1 != v2 { return false }
    }
    if _, ok := <- ch2; ok { return false }
    return true
}

func main() {
    ch := make(chan int)
    go Walk(tree.New(1), ch)
    for v := range ch {
        fmt.Println(v)
    }
    fmt.Println(Same(tree.New(1), tree.New(1)))
    fmt.Println(Same(tree.New(1), tree.New(2)))
}