forked from shuboc/LeetCode-2
-
Notifications
You must be signed in to change notification settings - Fork 0
/
insert-delete-getrandom-o1.py
94 lines (77 loc) · 2.4 KB
/
insert-delete-getrandom-o1.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
# Time: O(1)
# Space: O(n)
# Design a data structure that supports all following operations in O(1) time.
#
# insert(val): Inserts an item val to the set if not already present.
# remove(val): Removes an item val from the set if present.
# getRandom: Returns a random element from current set of elements.
# Each element must have the same probability of being returned.
#
# Example:
#
# // Init an empty set.
# RandomizedSet randomSet = new RandomizedSet();
#
# // Inserts 1 to the set. Returns true as 1 was inserted successfully.
# randomSet.insert(1);
#
# // Returns false as 2 does not exist in the set.
# randomSet.remove(2);
#
# // Inserts 2 to the set, returns true. Set now contains [1,2].
# randomSet.insert(2);
#
# // getRandom should return either 1 or 2 randomly.
# randomSet.getRandom();
#
# // Removes 1 from the set, returns true. Set now contains [2].
# randomSet.remove(1);
#
# // 2 was already in the set, so return false.
# randomSet.insert(2);
#
# // Since 1 is the only number in the set, getRandom always return 1.
# randomSet.getRandom();
from random import randint
class RandomizedSet(object):
def __init__(self):
"""
Initialize your data structure here.
"""
self.__set = []
self.__used = {}
def insert(self, val):
"""
Inserts a value to the set. Returns true if the set did not already contain the specified element.
:type val: int
:rtype: bool
"""
if val in self.__used:
return False
self.__set += val,
self.__used[val] = len(self.__set)-1
return True
def remove(self, val):
"""
Removes a value from the set. Returns true if the set contained the specified element.
:type val: int
:rtype: bool
"""
if val not in self.__used:
return False
self.__used[self.__set[-1]] = self.__used[val]
self.__set[self.__used[val]], self.__set[-1] = self.__set[-1], self.__set[self.__used[val]]
self.__used.pop(val)
self.__set.pop()
return True
def getRandom(self):
"""
Get a random element from the set.
:rtype: int
"""
return self.__set[randint(0, len(self.__set)-1)]
# Your RandomizedSet object will be instantiated and called as such:
# obj = RandomizedSet()
# param_1 = obj.insert(val)
# param_2 = obj.remove(val)
# param_3 = obj.getRandom()