ambroisie/blog
ambroisie/blog
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

posts: union-find: fix typos

Browse source
This commit is contained in:
Bruno BELANYI 2024-06-26 13:42:50 +00:00
parent fa2849bdba
commit eb2245db21
1 changed files with 3 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
content/posts/2024-06-24-union-find/index.md
View file

@ -86,7 +86,7 @@ A naive Implementation of `find(...)` is simple enough to write:
```python ```python
def find(self, elem: int) -> int: def find(self, elem: int) -> int:
# If `elem` is its own parent, then it is the root of the tree # If `elem` is its own parent, then it is the root of the tree
if (parent: = self._parent[elem]) == elem: if (parent := self._parent[elem]) == elem:
return elem return elem
# Otherwise, recurse on the parent # Otherwise, recurse on the parent
return self.find(parent) return self.find(parent)
@ -94,11 +94,11 @@ def find(self, elem: int) -> int:
However, going back up the chain of parents each time we want to find the root However, going back up the chain of parents each time we want to find the root
node (an `O(n)` operation) would make for disastrous performance. Instead we can node (an `O(n)` operation) would make for disastrous performance. Instead we can
do a small optimization called _path splitting. do a small optimization called _path splitting_.
```python ```python
def find(self, elem: int) -> int: def find(self, elem: int) -> int:
while (parent: = self._parent[elem]) != elem: while (parent := self._parent[elem]) != elem:
# Replace each parent link by a link to the grand-parent # Replace each parent link by a link to the grand-parent
elem, self._parent[elem] = parent, self._parent[parent] elem, self._parent[elem] = parent, self._parent[parent]
return elem return elem