158 lines
4.5 KiB
Python
158 lines
4.5 KiB
Python
"""
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Copyright 2009 Stutzbach Enterprises, LLC (daniel@stutzbachenterprises.com)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials provided
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with the distribution.
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3. The name of the author may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Vendorized heapdict implementation.
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This is a copy of the heapdict library to avoid external dependencies.
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Original source: https://pypi.org/project/HeapDict/
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"""
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from typing import Generic, TypeVar
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try:
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from collections.abc import MutableMapping
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except ImportError:
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from collections import MutableMapping
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KT = TypeVar("KT")
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VT = TypeVar("VT")
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def doc(s):
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if callable(s):
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s = s.__doc__
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def f(g):
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g.__doc__ = s
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return g
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return f
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class heapdict(MutableMapping, Generic[KT, VT]):
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__marker = object()
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def __init__(self, *args, **kw):
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self.heap = []
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self.d = {}
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self.update(*args, **kw)
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@doc(dict.clear)
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def clear(self):
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del self.heap[:]
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self.d.clear()
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@doc(dict.__setitem__)
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def __setitem__(self, key, value):
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if key in self.d:
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self.pop(key)
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wrapper = [value, key, len(self)]
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self.d[key] = wrapper
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self.heap.append(wrapper)
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self._decrease_key(len(self.heap) - 1)
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def _min_heapify(self, i):
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n = len(self.heap)
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h = self.heap
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while True:
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# calculate the offset of the left child
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l = (i << 1) + 1
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# calculate the offset of the right child
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r = (i + 1) << 1
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if l < n and h[l][0] < h[i][0]:
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low = l
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else:
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low = i
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if r < n and h[r][0] < h[low][0]:
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low = r
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if low == i:
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break
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self._swap(i, low)
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i = low
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def _decrease_key(self, i):
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while i:
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# calculate the offset of the parent
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parent = (i - 1) >> 1
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if self.heap[parent][0] < self.heap[i][0]:
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break
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self._swap(i, parent)
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i = parent
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def _swap(self, i, j):
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h = self.heap
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h[i], h[j] = h[j], h[i]
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h[i][2] = i
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h[j][2] = j
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@doc(dict.__delitem__)
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def __delitem__(self, key):
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wrapper = self.d[key]
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while wrapper[2]:
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# calculate the offset of the parent
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parentpos = (wrapper[2] - 1) >> 1
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parent = self.heap[parentpos]
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self._swap(wrapper[2], parent[2])
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self.popitem()
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@doc(dict.__getitem__)
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def __getitem__(self, key):
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return self.d[key][0]
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@doc(dict.__iter__)
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def __iter__(self):
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return iter(self.d)
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def popitem(self):
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"""D.popitem() -> (k, v), remove and return the (key, value) pair with lowest\nvalue; but raise KeyError if D is empty."""
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wrapper = self.heap[0]
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if len(self.heap) == 1:
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self.heap.pop()
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else:
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self.heap[0] = self.heap.pop()
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self.heap[0][2] = 0
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self._min_heapify(0)
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del self.d[wrapper[1]]
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return wrapper[1], wrapper[0]
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@doc(dict.__len__)
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def __len__(self):
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return len(self.d)
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def peekitem(self):
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"""D.peekitem() -> (k, v), return the (key, value) pair with lowest value;\n but raise KeyError if D is empty."""
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return (self.heap[0][1], self.heap[0][0])
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del doc
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__all__ = ["heapdict"]
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