程式碼一：在remove中涉及排序操作 時間複雜做不到O(1) 108ms
程式碼二：繼續用空間換時間 字典中儲存字典 能做到O(1) 127ms 執行時間還增加了 是沒有大的測試資料集嗎？
不知道集合刪除操作是不是O(1)?望告知

class RandomizedCollection(object):
    import random
    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.dict1={}
        self.list1=[]
        self.index=0

    def insert(self, val):
        """
        Inserts a value to the collection. Returns true if the collection did not already contain the specified element.
        :type val: int
        :rtype: bool
        """
        if val in self.dict1:
            self.dict1[val].append(self.index)
            self.list1.append(val)
            self.index+=1
            return False 
        else:
            self.dict1[val]=[self.index]
            self.list1.append(val)
            self.index+=1
            return True
    def remove(self, val):
        """
        Removes a value from the collection. Returns true if the collection contained the specified element.
        :type val: int
        :rtype: bool
        """
        if val in self.dict1:
            tmp = self.dict1[val].pop()
            if self.dict1[val]==[]:
                del self.dict1[val] 
            self.index-=1
            p=self.list1[tmp]
            q=self.list1[self.index]
            if p==q:
                
                self.list1.pop()
            else:
            
                self.list1[tmp]=q
                self.list1[self.index]=p
                self.dict1[q][-1]=tmp
                self.dict1[q].sort()
                self.list1.pop()
            
            return True 
        else:
            return False
 

class RandomizedCollection(object):
    import random
    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.dict1={}
        self.list1=[]
        self.index=0

    def insert(self, val):
        """
        Inserts a value to the collection. Returns true if the collection did not already contain the specified element.
        :type val: int
        :rtype: bool
        """
        if val in self.dict1:
            self.dict1[val][self.index]=True
            self.list1.append(val)
            self.index+=1
            return False 
        else:
            self.dict1[val]={self.index:True}
            self.list1.append(val)
            self.index+=1
            return True
    def remove(self, val):
        """
        Removes a value from the collection. Returns true if the collection contained the specified element.
        :type val: int
        :rtype: bool
        """
        if val in self.dict1:
            self.index-=1
            if self.index in self.dict1[val]:
                del self.dict1[val][self.index]
                if len(self.dict1[val])==0:
                    del self.dict1[val] 
                self.list1.pop()
            else:
                tmp = self.dict1[val].popitem()
                tmp=tmp[0]
                if len(self.dict1[val])==0:
                    del self.dict1[val] 

                p=self.list1[tmp]
                q=self.list1[self.index]
                self.list1[tmp]=q
                self.list1[self.index]=p
                self.dict1[q][tmp]=True
                del self.dict1[q][self.index]
                self.list1.pop()
            
            return True 
        else:
            return False
        

    def getRandom(self):
        """
        Get a random element from the collection.
        :rtype: int
        """
        return random.choice(self.list1)