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"""
Copyright (c) 2018 Intel Corporation
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
class DSUElem:
"""
An object that represents one DSU element.
"""
name = ''
parent = ''
rank = 1
def __init__(self, name):
self.name = name
self.parent = name
self.rank = 1
class DSU:
"""
Naive implementation of the "disjoint set union" data structure.
"""
map = dict()
def __init__(self, elems: list):
self.map = {elem.name: elem for elem in elems}
pass
def find_elem(self, name: str):
return self.map[name]
def find_parent(self, elem: DSUElem):
if elem.parent == elem.name:
return elem
parent_elem = self.find_parent(self.find_elem(elem.parent))
elem.parent = parent_elem.name
return parent_elem
def union(self, elem1: DSUElem, elem2: DSUElem):
elem1 = self.find_parent(elem1)
elem2 = self.find_parent(elem2)
if elem1.name == elem2.name: # already in the same set
return
if elem1.rank < elem2.rank:
elem1.parent = elem2.name
elif elem1.rank > elem2.rank:
elem2.parent = elem1.name
else:
elem1.parent = elem2.name
elem2.rank = elem2.rank + 1
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