添加 二叉树层序遍历的递归遍历

problems/0102.二叉树的层序遍历.md

@@ -205,6 +205,36 @@ class Solution {
 
 go: 
 
+```go
+/**
+102. 二叉树的递归遍历
+ */
+func levelOrder(root *TreeNode) [][]int {
+	arr := [][]int{}
+
+	depth := 0
+
+	var order func(root *TreeNode, depth int)
+
+	order = func(root *TreeNode, depth int) {
+		if root == nil {
+			return
+		}
+		if len(arr) == depth {
+			arr = append(arr, []int{})
+		}
+		arr[depth] = append(arr[depth], root.Val)
+
+		order(root.Left, depth+1)
+		order(root.Right, depth+1)
+	}
+
+	order(root, depth)
+
+	return arr
+}
+```
+
 ```go
 /**
 102. 二叉树的层序遍历