33 lines
833 B
Python
33 lines
833 B
Python
import random
|
|
|
|
class ListDict(object):
|
|
def __init__(self):
|
|
self.item_to_position = {}
|
|
self.items = []
|
|
|
|
def add_item(self, item):
|
|
if item in self.item_to_position:
|
|
return
|
|
self.items.append(item)
|
|
self.item_to_position[item] = len(self.items)-1
|
|
|
|
def remove_item(self, item):
|
|
position = self.item_to_position.pop(item)
|
|
last_item = self.items.pop()
|
|
if position != len(self.items):
|
|
self.items[position] = last_item
|
|
self.item_to_position[last_item] = position
|
|
|
|
def choose_random_item(self):
|
|
return random.choice(self.items)
|
|
|
|
def __contains__(self, item):
|
|
return item in self.item_to_position
|
|
|
|
def __iter__(self):
|
|
return iter(self.items)
|
|
|
|
def length(self):
|
|
return len(self.items)
|
|
|