feat: 700. Search in a Binary Search Tree

src/binary_search_tree/search_in_a_binary_search_tree/solution.py

@@ -0,0 +1,15 @@
+from typing import Optional
+from structures import TreeNode
+
+
+class Solution:
+    def searchBST(self, root: Optional[TreeNode], val: int) -> Optional[TreeNode]:
+        if not root:
+            return None
+
+        if root.val == val:
+            return root
+        elif root.val > val:
+            return self.searchBST(root.left, val)
+        else:
+            return self.searchBST(root.right, val)

test_utils/tree_builder.py

@@ -27,3 +27,25 @@ def from_list(values: list[Optional[int]]) -> Optional[TreeNode]:
             i += 1
 
         return root
+
+    @staticmethod
+    def to_list(root: Optional[TreeNode]) -> list[Optional[int]]:
+        if not root:
+            return []
+
+        result = []
+        queue = deque([root])
+
+        while queue:
+            node = queue.popleft()
+            if node:
+                result.append(node.val)
+                queue.append(node.left)
+                queue.append(node.right)
+            else:
+                result.append(None)
+
+        while result and result[-1] is None:
+            result.pop()
+
+        return result

tests/test_search_in_a_binary_search_tree.py

@@ -0,0 +1,13 @@
+import pytest
+from src.binary_search_tree.search_in_a_binary_search_tree.solution import Solution
+from test_utils import TreeBuilder
+
+
+@pytest.mark.parametrize(
+    "root, val, expected",
+    [([4, 2, 7, 1, 3], 2, [2, 1, 3]), ([4, 2, 7, 1, 3], 5, [])],
+)
+def test_search_bst(root, val, expected):
+    root = TreeBuilder.from_list(root)
+    solution = Solution()
+    assert TreeBuilder.to_list(solution.searchBST(root, val)) == expected