-
Notifications
You must be signed in to change notification settings - Fork 43
/
design_search_autocomplete_system.py
200 lines (168 loc) · 7.61 KB
/
design_search_autocomplete_system.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
"""
642 Design Search Autocomplete System
https://cheonhyangzhang.gitbooks.io/leetcode-solutions/content/642-design-search-autocomplete-system.html
Problem
Design a search autocomplete system for a search engine. Users may input a sentence (at least one word and end with a special character '#'). For each character they type except '#', you need to return the top 3 historical hot sentences that have prefix the same as the part of sentence already typed. Here are the specific rules:
The hot degree for a sentence is defined as the number of times a user typed the exactly same sentence before.
The returned top 3 hot sentences should be sorted by hot degree (The first is the hottest one). If several sentences have the same degree of hot, you need to use ASCII-code order (smaller one appears first).
If less than 3 hot sentences exist, then just return as many as you can.
When the input is a special character, it means the sentence ends, and in this case, you need to return an empty list. Your job is to implement the following functions:
The constructor function:
AutocompleteSystem(String[] sentences, int[] times): This is the constructor. The input is historical data. Sentences is a string array consists of previously typed sentences. Times is the corresponding times a sentence has been typed. Your system should record these historical data.
Now, the user wants to input a new sentence. The following function will provide the next character the user types:
List input(char c): The input c is the next character typed by the user. The character will only be lower-case letters ('a' to 'z'), blank space (' ') or a special character ('#'). Also, the previously typed sentence should be recorded in your system. The output will be the top 3 historical hot sentences that have prefix the same as the part of sentence already typed.
Example:
Operation: AutocompleteSystem(["i love you", "island","ironman", "i love leetcode"], [5,3,2,2])
The system have already tracked down the following sentences and their corresponding times:
"i love you" : 5 times
"island" : 3 times
"ironman" : 2 times
"i love leetcode" : 2 times
Now, the user begins another search:
Operation: input('i')
Output: ["i love you", "island","i love leetcode"]
Explanation:
There are four sentences that have prefix "i". Among them, "ironman" and "i love leetcode" have same hot degree. Since ' ' has ASCII code 32 and 'r' has ASCII code 114, "i love leetcode" should be in front of "ironman". Also we only need to output top 3 hot sentences, so "ironman" will be ignored.
Operation: input(' ')
Output: ["i love you","i love leetcode"]
Explanation:
There are only two sentences that have prefix "i ".
Operation: input('a')
Output: []
Explanation:
There are no sentences that have prefix "i a".
Operation: input('#')
Output: []
Explanation:
The user finished the input, the sentence "i a" should be saved as a historical sentence in system. And the following input will be counted as a new search.
Note: The input sentence will always start with a letter and end with '#', and only one blank space will exist between two words. The number of complete sentences that to be searched won't exceed 100. The length of each sentence including those in the historical data won't exceed 100. Please use double-quote instead of single-quote when you write test cases even for a character input. Please remember to RESET your class variables declared in class AutocompleteSystem, as static/class variables are persisted across multiple test cases. Please see here for more details.
"""
# V0
# V1
# IDEA : DICT TRIE
# http://bookshadow.com/weblog/2017/07/16/leetcode-design-search-autocomplete-system/
class TrieNode:
def __init__(self):
self.children = dict()
self.sentences = set()
class AutocompleteSystem(object):
def __init__(self, sentences, times):
"""
:type sentences: List[str]
:type times: List[int]
"""
self.buffer = ''
self.stimes = collections.defaultdict(int)
self.trie = TrieNode()
for s, t in zip(sentences, times):
self.stimes[s] = t
self.addSentence(s)
self.tnode = self.trie
def input(self, c):
"""
:type c: str
:rtype: List[str]
"""
ans = []
if c != '#':
self.buffer += c
if self.tnode: self.tnode = self.tnode.children.get(c)
if self.tnode: ans = sorted(self.tnode.sentences, key=lambda x: (-self.stimes[x], x))[:3]
else:
self.stimes[self.buffer] += 1
self.addSentence(self.buffer)
self.buffer = ''
self.tnode = self.trie
return ans
def addSentence(self, sentence):
node = self.trie
for letter in sentence:
child = node.children.get(letter)
if child is None:
child = TrieNode()
node.children[letter] = child
node = child
child.sentences.add(sentence)
# Your AutocompleteSystem object will be instantiated and called as such:
# obj = AutocompleteSystem(sentences, times)
# param_1 = obj.input(c)
### Test case : dev
# V1'
# https://blog.csdn.net/Sengo_GWU/article/details/82948834
class TrieNode():
def __init__(self):
self.children = collections.defaultdict(TrieNode)
self.isEnd = False
self.rank = 0
self.data = ''
class AutocompleteSystem(object):
def __init__(self, sentences, times):
self.root = TrieNode()
for i, sentence in enumerate(sentences):
self.addRecord(sentence, times[i])
self.keyWords = ''
def addRecord(self, sentence, time):
node = self.root
for c in sentence:
node = node.children[c]
node.isEnd = True
node.rank -= time
node.data = sentence
def input(self, c):
res = []
if c != '#':
self.keyWords += c
res = self.search(self.keyWords)
else:
self.addRecord(self.keyWords, 1)
self.keyWords = ''
return res
def search(self, sentence):
node = self.root
for c in sentence:
node = node.children.get(c)
if not node:
return []
res = self.dfs(node)
return [data for rank, data in sorted(res)[:3]]
def dfs(self, node):
res = []
if node:
if node.isEnd:
res.append([node.rank, node.data])
for child in node.children.values():
res.extend(self.dfs(child))
return res
# V1''
# https://zhuanlan.zhihu.com/p/99499171
class AutocompleteSystem:
def insert(self, w: str, t=1):
cur = self.root
for c in w:
if c not in cur:
cur[c] = {}
cur = cur[c]
if 'hot' not in cur:
cur['hot'] = {}
if w not in cur['hot']:
cur['hot'][w] = 0
cur['hot'][w] += t
def __init__(self, sentences: List[str], times: List[int]):
self.root = {}
self.w = ''
self.cur = self.root
for i, s in enumerate(sentences):
self.insert(s, times[i])
def input(self, c: str) -> List[str]:
if c == '#':
self.insert(self.w)
self.w = ''
self.cur = self.root
return []
self.w += c
if self.cur == None or c not in self.cur:
self.cur = None
return []
self.cur = self.cur[c]
return [k for k, v in sorted(self.cur['hot'].items(), key=lambda x: (-x[1], x[0]), reverse=False)][0:3]
# V2