class Median:
def __init__(self):
#unfortunatelly min and max have different interfaces
self.max = HeapMax()
self.min = []
def get(self):
diff = len(self.max.v) - len(self.min)
if diff > 0: #it should not be >1
key, obj = self.max.top()
return key
elif diff < 0:
return self.min[0]
else:
key, obj = self.max.top()
return (key + self.min[0]) / 2.0
def add(self, value):
sz = self.size()
if sz == 0:
#push it anywhere
self.max.push(value, None)
elif sz == 1:
if len(self.min) > 0:
right = self.min[0]
if value > right:
heappush(self.min, value)
else:
self.max.push(value, None)
else:
left, obj = self.max.top()
if value < left:
self.max.push(value, None)
else:
heappush(self.min, value)
else:
#for sure three are items in both the heaps
right = self.min[0]
if value > right:
heappush(self.min, value)
else:
self.max.push(value, None)
self.__rebalance()
def size(self):
return self.max.size() + len(self.min)
def __rebalance(self):
diff = self.max.size() - len(self.min)
if diff > 1:
value, obj = self.max.pop()
heappush(self.min, value)
elif diff < -1:
value = heappop(self.min)
self.max.push(value, None)
else:
pass
class Median: def __init__(self): #unfortunatelly min and max have different interfaces self.max=HeapMax() self.min=[] def get(self): diff=len(self.max.v)-len(self.min) if diff>0: #it should not be >1 key,obj=self.max.top() return key elif diff<0: return self.min[0] else: key,obj=self.max.top() return (key+self.min[0])/2.0 def add(self, value): sz=self.size() if sz == 0: #push it anywhere self.max.push(value,None) elif sz==1: if len(self.min)>0: right=self.min[0] if value>right: heappush(self.min,value) else: self.max.push(value,None) else: left, obj=self.max.top() if value<left: self.max.push(value,None) else: heappush(self.min,value) else: #for sure three are items in both the heaps right=self.min[0] if value>right: heappush(self.min,value) else: self.max.push(value,None) self.__rebalance() def size(self): return self.max.size()+len(self.min) def __rebalance(self): diff=self.max.size()-len(self.min) if diff>1: value,obj=self.max.pop() heappush(self.min,value) elif diff<-1: value=heappop(self.min) self.max.push(value,None) else: pass
def heap_sort(source: List[int]) -> List[int]:
heap = HeapMax()
for i in source:
heap.insert(HeapItem(i, None))
return [heap.get_item_max().priority for _ in range(heap.size())]
def build_heap(source: List[int]):
heap = HeapMax(source)
for i in range(heap.size() // 2, -1, -1):
heap.sift_down(i)
return heap
