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BinaryHeap.py
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59 lines (52 loc) · 1.74 KB
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# 构建树实现堆
class BinHeap:
def __init__(self):
self.heapList = [0]
self.currentSize = 0
#插入新结点后必要时交换子节点和父节点的位置保持堆的性质
def percUp(self, i):
while i//2 > 0:
if self.heapList[i] < self.heapList[i//2]:
temp = self.heapList[i//2]
self.heapList[i//2] = self.heapList[i]
self.heapList[i] = temp
i = i//2
# 插入节点
def insert(self, k):
self.heapList.append(k)
self.currentSize += 1
self.percUp(self.currentSize)
# 删除堆顶元素后, 交换堆尾和空堆顶的位置并实现元素的下沉
def percDown(self, i):
while (i*2) <= self.currentSize:
mc = self.minChild(i)
if self.heapList[i] > self.heapList[mc]:
temp = self.heapList[i]
self.heapList[i] = self.heapList[mc]
self.heapList[mc] = temp
i = mc
def minChild(self, i):
if i * 2 + 1 > self.currentSize:
return i * 2
else:
if self.heapList[i*2] < self.heapList[i*2+1]:
return i * 2
else:
return i * 2 + 1
def delMin(self):
retval = self.heapList[1]
self.heapList[1] = self.heapList[self.currentSize]
self.currentSize = self.currentSize - 1
self.heapList.pop()
self.percDown(1)
return retval
def buildHeap(self, alist):
i = len(alist) // 2
self.currentSize = len(alist)
self.heapList = [0] + alist[:]
while (i > 0):
self.percDown(i)
i = i - 1
return self.heapList
H = BinHeap()
print(H.buildHeap([9, 6, 5, 2, 3]))