Created
April 16, 2022 21:54
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CLFT onsite prep -- window_key_map
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""" | |
windowed k, v map | |
first version with t for debug | |
""" | |
class Node: | |
def __init__(self, time=0, val=0, key=0): | |
self.time = time | |
self.val = val | |
self.key = key | |
self.next = None | |
self.prev = None | |
def __repr__(self): | |
return '(key: {0}, value: {1}, time: {2})'.format(self.key, self.val, self.time) | |
class WindowedMap: | |
def __init__(self): | |
self.nodemap = dict() | |
self.head = Node() | |
self.tail = Node() | |
self.head.next, self.tail.prev = self.tail, self.head | |
self.sum = 0 | |
self.timeout = 5 | |
def remove(self, node): | |
# remove node from dll | |
prev, next = node.prev, node.next | |
prev.next, next.prev = next, prev | |
def insert(self, node): | |
# insert at the end | |
self.tail.prev.next = node | |
node.prev = self.tail.prev | |
node.next = self.tail | |
self.tail.prev = node | |
def put(self, key, value, t=0): | |
# timestamp = t | |
if key in self.nodemap: | |
self.sum -= self.nodemap[key].val | |
self.remove(self.nodemap[key]) | |
self.nodemap.pop(key) | |
if key not in self.nodemap: | |
self.sum += value | |
newnode = Node(t, value, key) | |
self.insert(newnode) | |
self.nodemap[key] = newnode | |
def get(self, key, t=0): | |
start = t - self.timeout | |
if key not in self.nodemap: | |
return -1 | |
if self.nodemap[key].time < start: | |
return -1 | |
return self.nodemap[key].val | |
def get_average(self, t=0): | |
# remove expired stuff, worst case O(n) | |
start = t - self.timeout | |
itr = self.head.next | |
while itr != self.tail: | |
nextnode = itr.next | |
if itr.time < start: | |
self.sum -= itr.val | |
self.nodemap.pop(itr.key) | |
self.remove(itr) | |
itr = nextnode | |
if len(self.nodemap) == 0: | |
return 0 | |
return self.sum / len(self.nodemap) |
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