65 lines
1.8 KiB
Python
65 lines
1.8 KiB
Python
"""
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Copyright (C) 2018-2020 Intel Corporation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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class DSUElem:
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"""
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An object that represents one DSU element.
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"""
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name = ''
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parent = ''
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rank = 1
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def __init__(self, name):
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self.name = name
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self.parent = name
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self.rank = 1
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class DSU:
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"""
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Naive implementation of the "disjoint set union" data structure.
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"""
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map = dict()
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def __init__(self, elems: list):
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self.map = {elem.name: elem for elem in elems}
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pass
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def find_elem(self, name: str):
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return self.map[name]
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def find_parent(self, elem: DSUElem):
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if elem.parent == elem.name:
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return elem
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parent_elem = self.find_parent(self.find_elem(elem.parent))
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elem.parent = parent_elem.name
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return parent_elem
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def union(self, elem1: DSUElem, elem2: DSUElem):
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elem1 = self.find_parent(elem1)
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elem2 = self.find_parent(elem2)
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if elem1.name == elem2.name: # already in the same set
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return
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if elem1.rank < elem2.rank:
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elem1.parent = elem2.name
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elif elem1.rank > elem2.rank:
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elem2.parent = elem1.name
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else:
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elem1.parent = elem2.name
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elem2.rank = elem2.rank + 1
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