- BinaryHeap() 创建一个新的,空的二叉堆。
- insert(k) 向堆添加一个新项。
- findMin() 返回具有最小键值的项,并将项留在堆中。
- delMin() 返回具有最小键值的项,从堆中删除该项。
- 如果堆是空的,isEmpty() 返回 true,否则返回 false。
- size() 返回堆中的项数。
- buildHeap(list) 从键列表构建一个新的堆。
from pythonds.trees.binheap import BinHeap bh = BinHeap() bh.insert(5) bh.insert(7) bh.insert(3) bh.insert(11) print(bh.delMin()) print(bh.delMin()) print(bh.delMin()) print(bh.delMin())
class BinHeap: def __init__(self): self.heapList = [0] self.currentSize = 0 def percUp(self,i): while i // 2 > 0: if self.heapList[i] < self.heapList[i // 2]: tmp = self.heapList[i // 2] self.heapList[i // 2] = self.heapList[i] self.heapList[i] = tmp i = i // 2 def insert(self,k): self.heapList.append(k) self.currentSize = self.currentSize + 1 self.percUp(self.currentSize) def percDown(self,i): while (i * 2) <= self.currentSize: mc = self.minChild(i) if self.heapList[i] > self.heapList[mc]: tmp = self.heapList[i] self.heapList[i] = self.heapList[mc] self.heapList[mc] = tmp 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 bh = BinHeap() bh.buildHeap([9,5,6,2,3]) print(bh.delMin()) print(bh.delMin()) print(bh.delMin()) print(bh.delMin()) print(bh.delMin())