Sum binary tree path ints

leetcode/stuff.py

@@ -251,3 +251,31 @@ def collect_binary_tree_levels(
     yield (level, node)
     yield from collect_binary_tree_levels(level + 1, node.right)
     yield from collect_binary_tree_levels(level + 1, node.left)
+
+
+def sum_binary_tree_path_ints(root: stdlib.Node | None) -> int:
+    path_ints: list[int] = []
+
+    for path in collect_binary_tree_paths(root):
+        path_ints.append(int("".join([str(node.val) for node in path])))
+
+    return sum(path_ints)
+
+
+def collect_binary_tree_paths(
+    node: stdlib.Node | None,
+) -> typing.Iterator[list[stdlib.Node]]:
+    if node is None:
+        return
+
+    if node.right is None and node.left is None:
+        yield [node]
+        return
+
+    if node.right is not None:
+        for path in collect_binary_tree_paths(node.right):
+            yield [node] + path
+
+    if node.left is not None:
+        for path in collect_binary_tree_paths(node.left):
+            yield [node] + path

leetcode/test_stuff.py

@@ -177,3 +177,20 @@ def test_connect_binary_tree_right(
     connected, serialized = stuff.connect_binary_tree_right(root)
     assert connected is not None
     assert serialized == expected
+
+
+@pytest.mark.parametrize(
+    ("root", "expected"),
+    [
+        (
+            stdlib.Node(
+                4,
+                right=stdlib.Node(0),
+                left=stdlib.Node(9, right=stdlib.Node(1), left=stdlib.Node(5)),
+            ),
+            1026,
+        ),
+    ],
+)
+def test_connect_binary_tree_sum_numbers(root: stdlib.Node | None, expected: int):
+    assert stuff.sum_binary_tree_path_ints(root) == expected