[LC] feat: top k frequent elements (bst)

Author: HaJunYoo

kth-smallest-element-in-a-bst/hajunyoo.py

@@ -0,0 +1,30 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+from collections import defaultdict
+
+
+class Solution:
+    def kthSmallest(self, root: Optional[TreeNode], k: int) -> int:
+
+        self.count = 0
+        self.result = 0
+
+        def dfs(node):
+            if not node:
+                return
+
+            dfs(node.left)
+
+            self.count += 1
+            if self.count == k:
+                self.result = node.val
+                return
+
+            dfs(node.right)
+
+        dfs(root)
+        return self.result