update

oj/algorithms/binarytree/traversal.go

@@ -0,0 +1,53 @@
+package main
+
+import "fmt"
+
+type node struct {
+	val   int
+	left  *node
+	right *node
+}
+
+func main() {
+	n8 := node{8, nil, nil}
+	n7 := node{7, nil, nil}
+	n6 := node{6, &n7, &n8}
+	n5 := node{5, nil, nil}
+	n4 := node{4, nil, &n6}
+	n3 := node{3, nil, &n5}
+	n2 := node{2, &n4, nil}
+	n1 := node{1, &n2, &n3}
+	fmt.Println("preorder: ")
+	preorder(&n1)
+	fmt.Println("\ninorder: ")
+	inorder(&n1)
+	fmt.Println("\npostorder: ")
+	postorder(&n1)
+}
+
+func preorder(root *node) {
+	if root == nil {
+		return
+	}
+	fmt.Printf("%d ", root.val)
+	preorder(root.left)
+	preorder(root.right)
+}
+
+func inorder(root *node) {
+	if root == nil {
+		return
+	}
+	inorder(root.left)
+	fmt.Printf("%d ", root.val)
+	inorder(root.right)
+}
+
+func postorder(root *node) {
+	if root == nil {
+		return
+	}
+	postorder(root.left)
+	postorder(root.right)
+	fmt.Printf("%d ", root.val)
+}