exercise: complete the exercise Equivalent Binary Trees with goroutine and channel

exercise/equal-binary-tree/README.md

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+## Test cases
+
+
+
+### Test Case 1
+
+```
+fmt.Println(Same(tree.New(1), tree.New(1)))
+```
+
+**output**
+```
+
+```
+
+
+### Test Case 2
+
+```
+t := tree.New(1)
+fmt.Println(Same(t, t))
+```
+
+**output**
+```
+ch2
+10
+ch1
+10
+ch2
+5
+ch1
+5
+ch2
+3
+ch1
+3
+ch2
+2
+ch1
+2
+ch2
+7
+ch1
+7
+ch2
+9
+ch1
+9
+ch2
+8
+ch1
+8
+ch2 done
+0
+true
+```
+
+
+
+### Test Case 3
+
+```
+fmt.Println(Same(tree.New(1), tree.New(2)))
+```
+
+**output**
+

exercise/equal-binary-tree/main.go

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+package main
+
+import (
+	"fmt"
+
+	"golang.org/x/tour/tree"
+)
+
+func Walk(t *tree.Tree, ch chan int) {
+	walk(t, ch)
+	close(ch)
+}
+
+// walk traverses the tree by the pre-order
+func walk(t *tree.Tree, ch chan int) {
+	if t != nil {
+		ch <- t.Value
+
+		walk(t.Left, ch)
+
+		walk(t.Right, ch)
+	}
+
+}
+
+func Same(t1, t2 *tree.Tree) bool {
+
+	ch1 := make(chan int)
+	ch2 := make(chan int)
+
+	go Walk(t1, ch1)
+	go Walk(t2, ch2)
+
+	x, y := 0, 0
+	ok := true
+	for {
+		select {
+		case x, ok = <-ch1:
+			if !ok {
+				return true
+			}
+			y = <-ch2
+			if x != y {
+				return false
+			}
+
+		case x, ok = <-ch2:
+			if !ok {
+				fmt.Println("ch2 done")
+				fmt.Println(x)
+				return true
+			}
+			fmt.Println("ch2")
+			fmt.Println(x)
+			y = <-ch1
+			fmt.Println("ch1")
+			fmt.Println(y)
+			if x != y {
+				return false
+			}
+		}
+	}
+
+	return true
+}
+
+func main() {
+
+	// fmt.Println(Same(tree.New(1), tree.New(1)))
+
+	t := tree.New(1)
+	fmt.Println(Same(t, t))
+
+	// fmt.Println(Same(tree.New(1), tree.New(2)))
+}