tour_69.go

// sri's solution for http://tour.golang.org/#69
// Exercise: Equivalent Binary Trees

package main

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

func Walk(t *tree.Tree, ch chan int, top bool) {
    if t == nil {
        return
    }
    Walk(t.Left, ch, false)
    ch <- t.Value
    Walk(t.Right, ch, false)
    if top {
        // not sure how if this is the best way
        // to signal eof on channel
        close(ch)
    }
}

func Same(t1, t2 *tree.Tree) bool {
    c1 := make(chan int)
    c2 := make(chan int)
    go Walk(t1, c1, true)
    go Walk(t2, c2, true)
    for {
        v1, ok1 := <- c1
        v2, ok2 := <- c2
        if ok1 && ok2 {
            if v1 != v2 {
                return false
            }
        } else if !ok1 && !ok2 {
            return true
        } else {
            return false
        }
    }
    return true
}

func main() {
    fmt.Println(Same(tree.New(1), tree.New(1))) // true
    fmt.Println(Same(tree.New(1), tree.New(2))) // false
}