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380-InsertDeleteGetRandomO1.py
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380-InsertDeleteGetRandomO1.py
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#思路: 这是一道设计题,使用set集合数据结构可以满足要求,需注意,获取随机值的时候,因为set没有key可以用来取值,所以转成list,再利用随机key完成功能。
import random
class RandomizedSet(object):
def __init__(self):
"""
Initialize your data structure here.
"""
self.RandomSet = set([])
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 not in self.RandomSet:
self.RandomSet.add(val)
return True
else:
return False
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 in self.RandomSet:
self.RandomSet.remove(val)
return True
return False
def getRandom(self):
"""
Get a random element from the set.
:rtype: int
"""
if not self.RandomSet:
return None
RandomList = list(self.RandomSet)
randomNum = random.randint(0, len(RandomList)-1) #randint取随机数是两边都包含的闭区间
return RandomList[randomNum]
# 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()