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

tree_comparison.go

package main

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

//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) {
	if t.Left != nil {
		Walk(t.Left, ch)
	}
	
	ch <- t.Value
	
	if t.Right != nil {
		Walk(t.Right, ch)
	}
}

func Walk2(root *tree.Tree, t *tree.Tree, ch chan int) {
	if t.Left != nil {
		Walk2(root, t.Left, ch)
	}
	
	ch <- t.Value
	
	if t.Right != nil {
		Walk2(root, t.Right, ch)
	}
	
	if root == 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 Walk2(t1, t1, ch1)
	go Walk2(t2, t2, ch2)
	
	for {
		v1, ok1 := <- ch1		
		v2, ok2 := <- ch2
		
		if ok1 && ok2 {
			if v1 != v2 {
				return false
			}
		} else if !ok1 && !ok2 {
			return true
		} else {			
			return false
		}
	}
	
	return true
}

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