Week 13 Kth Smallest Element in a BST Solution

Author: doh6077

kth-smallest-element-in-a-bst/doh6077.py

@@ -0,0 +1,27 @@
+# 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
+class Solution:
+    # Time Complexity O(N)
+    def kthSmallest(self, root: Optional[TreeNode], k: int) -> int:
+        ans = []
+        final = [0]
+
+        def dfs(node):
+            
+            if not node:
+                return 
+            
+            dfs(node.left)
+
+            ans.append(node.val)
+            if len(ans) == k:
+                final[0] = node.val
+            if len(ans) < k:
+                dfs(node.right)
+        dfs(root)
+        return final[0]
+