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from abc import ABCMeta, abstractmethod |
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from pyalgs.algorithms.commons import util |
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from pyalgs.data_structures.commons.queue import Queue |
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class HashedMap(object): |
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__metaclass__ = ABCMeta |
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@abstractmethod |
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def put(self, key, value): |
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pass |
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@abstractmethod |
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def get(self, key): |
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pass |
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@abstractmethod |
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def delete(self, key): |
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pass |
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@abstractmethod |
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def size(self): |
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pass |
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@abstractmethod |
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def is_empty(self): |
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pass |
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@abstractmethod |
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def keys(self): |
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pass |
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@abstractmethod |
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def contains_key(self, key): |
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pass |
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@staticmethod |
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def create(): |
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return HashedMapWithSeparateChaining() |
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class Node(object): |
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key = None |
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value = None |
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next_node = None |
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def __init__(self, key=None, value=None): |
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self.key = key |
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self.value = value |
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class HashedMapWithSeparateChaining(HashedMap): |
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M = 97 |
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id = None |
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N = 0 |
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def __init__(self): |
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self.id = [Node()] * self.M |
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def hash(self, key): |
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return (hash(key) & 0x7fffffff) % self.M |
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def is_empty(self): |
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return self.N == 0 |
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def contains_key(self, key): |
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return self.get(key) is not None |
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def keys(self): |
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queue = Queue.create() |
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for i in range(self.M): |
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self.collect_keys(i, queue) |
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return queue.iterate() |
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def collect_keys(self, i, queue): |
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x = self.id[i] |
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while x is not None: |
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queue.enqueue(x.key) |
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x = x.next_node |
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def size(self): |
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return self.N |
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def get(self, key): |
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i = self.hash(key) |
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x = self.id[i] |
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while x is not None: |
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if util.cmp(x.key, key) == 0: |
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return x.value |
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x = x.next_node |
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return None |
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94
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def delete(self, key): |
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i = self.hash(key) |
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x = self.id[i] |
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prev_node = None |
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while x is not None: |
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if util.cmp(x.key, key) == 0: |
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value = x.value |
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next_node = x.next_node |
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self.N -= 1 |
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if prev_node is not None: |
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prev_node.next_node = next_node |
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if self.id[i] == x: |
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self.id[i] = None |
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return value |
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prev_node = x |
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x = x.next_node |
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return None |
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111
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112
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def put(self, key, value): |
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i = self.hash(key) |
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x = self.id[i] |
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while x is not None: |
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if util.cmp(x.key, key) == 0: |
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x.value = value |
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return |
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x = x.next_node |
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old_first = self.id[i] |
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self.id[i] = Node(key, value) |
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self.id[i].next_node = old_first |
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self.N += 1 |
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chen0040 /
pyalgs
