Tour of Go: Exercise: Equivalent Binary Trees

exercize-equivalent-binary-trees.go

package main

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

// Walk walks the tree t sending all values (sorted ascending)
// 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)
	}
}

// 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) // ch1 will receive all values from tree 1 (sorted)
	go Walk(t2, ch2) // ch2 will receive all values from tree 2 (sorted)
	
	for i := 0; i<10; i++ { // task clearly says it's always 10 items in tree
	 // all pairs should match
		if <- ch1 != <- ch2 { // if not matches
			return false //  trees are not equivalent
		}
	}
	return true // if we get here:  trees are equivalent
}

func main() {
	fmt.Println("1)", Same(tree.New(1), tree.New(1)))
	fmt.Println("2)", Same(tree.New(1), tree.New(2)))
}

output.txt

1) true
2) false