208. Implement Trie (Prefix Tree)
class Trie:
def __init__(self):
"""
Initialize your data structure here.
"""
self.tree = []
def insert(self, word: str) -> None:
"""
Inserts a word into the trie.
"""
self.tree.append(word)
def search(self, word: str) -> bool:
"""
Returns if the word is in the trie.
"""
return word in self.tree
def startsWith(self, prefix: str) -> bool:
"""
Returns if there is any word in the trie that starts with the given prefix.
"""
for item in self.tree:
if item.startswith(prefix):
return True
return False
648. Replace Words
class Solution:
def replaceWords(self, roots: List[str], sentence: str) -> str:
new_dic = {}
for root in roots:
length = len(root)
new_dic[root] = length
new_dic = sorted(new_dic.keys())
sentence = sentence.split()
new_sentence = sentence.copy()
for root in new_dic:
for i in range(len(sentence)):
if sentence[i][:len(root)] == root:
sentence[i] = "1"
new_sentence[i] = root
output = ""
for word in new_sentence:
output = output + " " + word
return output.lstrip()676. Implement Magic Dictionary 这个题可能是我AC的最好的一个题了
Runtime: 20 ms, faster than 99.81% of Python3 online submissions for Implement Magic Dictionary.
Memory Usage: 12.8 MB, less than 100.00% of Python3 online submissions for Implement Magic Dictionary.
class MagicDictionary:
def __init__(self):
"""
Initialize your data structure here.
"""
self.roots = []
def buildDict(self, root: List[str]) -> None:
"""
Build a dictionary through a list of words
"""
self.roots += root
def search(self, word: str) -> bool:
"""
Returns if there is any word in the trie that equals to the given word after modifying exactly one character
"""
res = [0]
for root in self.roots:
if len(root) == len(word):
temp = 0
for i in range(len(root)):
if root[i] != word[i]:
temp +=1
res.append(temp)
if len(res) == 1:
return False
if 1 in res :
return True
else:
return False
677. Map Sum Pairs 这个题AC的效果也比较好
Runtime: 32 ms, faster than 92.23% of Python3 online submissions for Map Sum Pairs.
Memory Usage: 12.8 MB, less than 100.00% of Python3 online submissions for Map Sum Pairs.
class MapSum:
def __init__(self):
"""
Initialize your data structure here.
"""
self.dic = {}
def insert(self, key: str, val: int) -> None:
self.dic[key] = val
def sum(self, prefix: str) -> int:
res = 0
for key in self.dic.keys():
if key.startswith(prefix):
res += self.dic[key]
return res
