Python排序搜索基本算法之堆排序实例详解

def fixUp(a): #在堆尾加入新元素，fixUp恢复堆的条件
  k=len(a)-1
  while k>1 and a[k//2]<a[k]:
    a[k//2],a[k]=a[k],a[k//2]
    k=k//2
def fixDown(a): #取a[1]返回的值，然后把a[N]移到a[1]，fixDown来恢复堆的条件
  k=1
  N=len(a)-1
  while 2*k<=N:
    j=2*k
    if j<N and a[j]<a[j+1]:
      j+=1
    if a[k]<a[j]:
      a[k],a[j]=a[j],a[k]
      k=j
    else:
      break
def insert(a,elem):
  a.append(elem)
  fixUp(a)
def delMax(a):
  maxElem=a[1]
  N=len(a)
  if N<=1:
    print('There\'s none element in the list')
    return -1
  if N==2:
    return a[1]
  else:
    a[1]=a.pop()
    fixDown(a)
    return maxElem
data=[-1,] #第一个元素不用，占位
insert(data,26)
insert(data,5)
insert(data,77)
insert(data,1)
insert(data,61)
insert(data,11)
insert(data,59)
insert(data,15)
insert(data,48)
insert(data,19)
result=[]
N=len(data)-1
for i in range(N):
  print(data)
  result.append(delMax(data))
print(result)

[-1, 77, 61, 59, 48, 19, 11, 26, 1, 15, 5]
[-1, 61, 48, 59, 15, 19, 11, 26, 1, 5]
[-1, 59, 48, 26, 15, 19, 11, 5, 1]
[-1, 48, 19, 26, 15, 1, 11, 5]
[-1, 26, 19, 11, 15, 1, 5]
[-1, 19, 15, 11, 5, 1]
[-1, 15, 5, 11, 1]
[-1, 11, 5, 1]
[-1, 5, 1]
[-1, 1]
[77, 61, 59, 48, 26, 19, 15, 11, 5, 1]

def fixDown(a,k,n): #自顶向下堆化，从k开始堆化
  N=n-1
  while 2*k<=N:
    j=2*k
    if j<N and a[j]<a[j+1]: #选出左右孩子节点中更大的那个
      j+=1
    if a[k]<a[j]:
      a[k],a[j]=a[j],a[k]
      k=j
    else:
      break
def heapSort(l):
  n=len(l)-1
  for i in range(n//2,0,-1):
    fixDown(l,i,len(l))
  while n>1:
    l[1],l[n]=l[n],l[1]
    fixDown(l,1,n)
    n-=1
  return l[1:]
l=[-1,26,5,77,1,61,11,59,15,48,19] #第一个元素不用，占位
res=heapSort(l)
print(res)

[1, 5, 11, 15, 19, 26, 48, 59, 61, 77]