添加新题目

二叉树/二叉搜索树中第K小的元素/main.go

@@ -0,0 +1,27 @@
+package main
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func main() {
+
+}
+func kthSmallest(root *TreeNode, k int) int {
+	var helper func(root *TreeNode) []int
+	helper = func(root *TreeNode) []int {
+		if root == nil {
+			return []int{}
+		}
+		tmp := make([]int, 0)
+		tmp = append(tmp, helper(root.Left)...)
+		tmp = append(tmp, root.Val)
+		tmp = append(tmp, helper(root.Right)...)
+
+		return tmp
+	}
+	res := helper(root)
+	return res[k-1]
+}