heapTree

class BinHeap:
    def __init__(self):
        self.heapList = [0]
        self.currentSize = 0

    def perUp(self,i):
        while i//2 > 0:
            if self.heapList[i] < self.heapList[i//2]:
                tmp = self.heapList[i]
                self.heapList[i] = self.heapList[i//2]
                self.heapList[i//2] = tmp
            i = i//2

    def insert(self,k):
        self.heapList.append(k)
        self.currentSize = self.currentSize + 1
        self.perUp(self.currentSize)

    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 perDown(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 delMin(self):
        retval = self.heapList[1]
        self.heapList[1] = self.heapList[self.currentSize]
        self.currentSize = self.currentSize - 1
        self.heapList.pop()
        self.perDown(1)
        return retval

    def buildHeap(self,alist):
        i = len(alist)//2
        self.currentSize = len(alist)
        self.heapList = [0] + alist[:]
        while(i > 0):
            self.perDown(i)
            i = i - 1