/
trie.py
62 lines (53 loc) · 1.52 KB
/
trie.py
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class Trie():
"""
Trie class for lists/tuples, or any ordered data type (can slice)
"""
def __init__(self):
self.children = dict()
def __setitem__(self, key, val):
"""
can store data at a node on the trie
"""
if len(key) == 0:
self.data = val
else:
if not key[0] in self.children:
self.children[key[0]] = Trie()
self.children[key[0]][key[1:]] = val
def __getitem__(self, key):
"""
retrieve data from a node on the trie
"""
if len(key) == 0:
return self.data
else:
return self.children[key[0]][key[1:]]
def contains(self, key):
"""
check if trie contains node for this word
"""
if len(key) == 0:
return True
elif key[0] in self.children:
return self.children[key[0]].contains(key[1:])
else:
return False
def add(self, key):
"""
add a key to the trie
"""
if len(key) > 0:
if not key[0] in self.children:
self.children[key[0]] = Trie()
self.children[key[0]].add(key[1:])
def nodes(self):
"""
return a list of nodes
this is done using a depth-first iteration over the trie
"""
w = []
for c in self.children.keys():
w.append((c,))
for wc in self.children[c].nodes():
w.append((c,) + wc)
return w