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from abc import ABCMeta, abstractmethod |
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from pyalgs.data_structures.commons.queue import Queue |
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class SearchTries(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 is_empty(self): |
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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 delete(self, key): |
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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 keysWithPrefix(self, prefix): |
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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 RWaySearchTries() |
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class Node(object): |
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nodes = None |
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value = None |
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R = 256 |
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def __init__(self): |
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self.nodes = [None] * Node.R |
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class RWaySearchTries(SearchTries): |
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root = None |
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N = 0 |
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def contains_key(self, key): |
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x = self._get(self.root, key, 0) |
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if x is None: |
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return None |
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return x.value |
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def keysWithPrefix(self, prefix): |
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x = self._get(self.root, prefix, 0) |
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if x is None: |
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return None |
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queue = Queue.create() |
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self.collect(x, prefix, queue) |
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return queue.iterate() |
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def keys(self): |
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queue = Queue.create() |
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self.collect(self.root, '', queue) |
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return queue.iterate() |
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def collect(self, x, prefix, queue): |
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if x is None: |
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return |
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if x.value is not None: |
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queue.enqueue(prefix) |
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return |
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for r in range(Node.R): |
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self.collect(x.nodes[r], prefix + str(chr(r)), queue) |
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def is_empty(self): |
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return self.N == 0 |
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def get(self, key): |
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x = self._get(self.root, key, 0) |
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if x is not None: |
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return x.value |
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return None |
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def _get(self, x, key, d): |
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if x is None: |
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return None |
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if len(key) == d: |
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return x |
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return self._get(x.nodes[self.char_at(key, d)], key, d + 1) |
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def delete(self, key): |
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self.root = self._delete(self.root, key, 0) |
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def _delete(self, x, key, d): |
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if x is None: |
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return None |
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if len(key) == d: |
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if x.value is not None: |
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self.N -= 1 |
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return None |
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c = self.char_at(key, d) |
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x.nodes[c] = self._delete(x.nodes[c], key, d + 1) |
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return x |
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def put(self, key, value): |
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self.root = self._put(self.root, key, value, 0) |
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def _put(self, x, key, value, d): |
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if x is None: |
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x = Node() |
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if len(key) == d: |
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if x.value is None: |
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self.N += 1 |
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x.value = value |
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return x |
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c = self.char_at(key, d) |
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x.nodes[c] = self._put(x.nodes[c], key, value, d + 1) |
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return x |
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def char_at(self, key, d): |
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return ord(key[d]) |
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143
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def size(self): |
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return self.N |
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chen0040 /
pyalgs
