[硕.Love Python] Heap(堆)

class  MinHeap( object ):
    def  __init__( self , iterable = ()):
        self .array  =  [ None ]
        self .array.extend(iterable)
        self .build()

    def  build( self ):
        a, size  =  self .array,  self .size()
        for  i  in  xrange (size  /  2 ,  0 ,  - 1 ):
            c  =  2  *  i
            while  c < =  size:
                if  c  +  1  < =  size  and  a[c + 1 ] < a[c]:
                    c  + =  1

                if  a[c] > a[c / 2 ]:
                    break

                a[c], a[c / 2 ]  =  a[c / 2 ], a[c]
                c  * =  2

    def  insert( self , k):
        self .array.append(k)
        a, i  =  self .array,  self .size()

        while  i >  1  and  k < a[i / 2 ]:
            a[i]  =  a[i / 2 ]
            i  / =  2

        a[i]  =  k

    def  pop( self ):
        size  =  self .size()
        if  size  = =  0 :
            raise  IndexError( 'pop from empty heap' )

        a  =  self .array
        res  =  a[ 1 ]
        last  =  a.pop()
        size  - =  1

        if  size >  0 :
            c  =  2  *  1

            while  c < =  size:
                if  c  +  1  < =  size  and  a[c + 1 ] < a[c]:
                    c  + =  1

                if  a[c] > =  last:
                    break

                a[c / 2 ]  =  a[c]
                c  * =  2

            a[c / 2 ]  =  last

        return  res

    def  size( self ):
        return  len ( self .array)  -  1

if  __name__  = =  '__main__' :
    from  random  import  shuffle
    data  =  range ( 50 )
    shuffle(data)
    print  data
    h  =  MinHeap(data)

    for  _  in  xrange ( len (data)):
         print  h.pop()

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