package main

import (
	"fmt"
	"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) {
	walkRecurse(t, ch)
	close(ch)
}

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

// Same determines whether the trees
// t1 and t2 contain the same values.
func Same(t1, t2 *tree.Tree) bool {
	t1Ch := make(chan int)
	t2Ch := make(chan int)
	
	go Walk(t1, t1Ch)
	go Walk(t2, t2Ch)
	
	t1Values := map[int]struct{}{}
	for v1 := range t1Ch {
		if _, seen := t1Values[v1]; !seen {
			t1Values[v1] = struct{}{}
		}
	}
	
	for v2 := range t2Ch {
		if _, seen := t1Values[v2]; !seen {
			return false
		}	
	}
	
	return true
}

func main() {
	t := tree.New(1)
	values := make(chan int)
	go Walk(t, values)
	
	for v := range values {
		fmt.Println(v)
	}
	
	t1, t2 := tree.New(1), tree.New(2)
	fmt.Println(Same(t1, t2))
}