This commit is contained in:
Siddhant Jain 2025-01-13 17:02:12 -05:00
commit 419ccccf24

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@ -33,7 +33,7 @@ def create_sparse(max_node: int, parent: list[list[int]]) -> list[list[int]]:
For example, consider a small tree where:
- Node 1 is the root (its parent is 0),
- Nodes 2 and 3 have parent 1.
We set up the parent table for only two levels (row 0 and row 1)
for max_node = 3. (Note that in practice the table has many rows.)
@ -57,11 +57,18 @@ def lowest_common_ancestor(
) -> int:
"""
Return the lowest common ancestor (LCA) of nodes u and v in a tree.
<<<<<<< HEAD
The lists ``level`` and ``parent`` must be precomputed. ``level[i]`` is the depth
of node i, and ``parent`` is a sparse table where parent[0][i] is the direct parent
of node i.
=======
The lists `level` and `parent` must be precomputed. `level[i]` is the depth of node i,
and `parent` is a sparse table where parent[0][i] is the direct parent of node i.
>>>>>>> 097e9c6149e80f095be1b3dbef1c04ff94a7325a
>>> # Consider a simple tree:
>>> # 1
>>> # / \\
@ -136,6 +143,7 @@ def main() -> None:
sparse table and compute several lowest common ancestors.
The sample tree used is:
<<<<<<< HEAD
1
/ | \
@ -145,6 +153,17 @@ def main() -> None:
/ \\ | / \\
9 10 11 12 13
=======
1
/ | \
2 3 4
/ / \\ \\
5 6 7 8
/ \\ | / \\
9 10 11 12 13
>>>>>>> 097e9c6149e80f095be1b3dbef1c04ff94a7325a
The expected lowest common ancestors are:
- LCA(1, 3) --> 1
- LCA(5, 6) --> 1
@ -154,7 +173,7 @@ def main() -> None:
- LCA(8, 8) --> 8
To test main() without it printing to the console, we capture the output.
>>> import sys
>>> from io import StringIO
>>> backup = sys.stdout