求问Python归并排序求逆序数方法，python逆序,class nx:

求问Python归并排序求逆序数方法，python逆序,class nx:

class nx:      count = 0    def __init__(self):            self.str_list=[]        self.N = int(raw_input().strip())        for _ in xrange(self.N):            self.str_list.append(raw_input().strip())        print self.count_inversion(self.str_list)    def merge(self, ListA, ListB):        self.newlist = []        while ListA and ListB:            if ListA[0] > ListB[0]:               self.newlist.append(ListB[0])               ListB = ListB[1:]               self.count += len(ListA)               print str(len(ListA))+'****   '            else:               self.newlist.append(ListA[0])               ListA =ListA[1:]                 if ListA:            self.newlist = self.newlist + ListA          elif ListB:            self.newlist = self.newlist + ListB                return self.newlist           def merge_sort(self, A):        if len(A) == 1:            return A        else:            self.middle = len(A)/2                    print '**************'            print 'Ais '+str(A)            print 'middle is '+ str(self.middle)            print 'zuo'            print A[:self.middle]            print 'you'            print A[self.middle:]            self.sa1 = self.merge_sort(A[:self.middle])            self.sa2 = self.merge_sort(A[self.middle:])            return self.merge(self.sa1, self.sa2)    def count_inversion(self, sequence):        self.merge_sort(sequence)        return self.count    if __name__ == '__main__':        nx()

结果:

Ais ['2', '4', '3', '1']
middle is 2
zuo
['2', '4']
you
['3', '1']

Ais ['2', '4']
middle is 1
zuo
['2']
you
['4']

    ****************为什么会这样    Ais ['4', '3', '1']    middle is 1    zuo    ['4']    you    ['3', '1']    ****************

Ais ['3', '1']
middle is 1
zuo
['3']
you
['1']

我知道了，python局部变量问题

class nx:
def init(self):
self.count = 0
self.str_list=[]
self.N = int(raw_input().strip())
for _ in xrange(self.N):
self.str_list.append(raw_input().strip())
print self.count_inversion(self.str_list)

def merge(self, ListA, ListB):    newlist = []    while ListA and ListB:        if int(ListA[0]) > int(ListB[0]):           self.count += len(ListA)           newlist.append(ListB.pop(0))                       else:           newlist.append(ListA.pop(0))     return newlist + ListA + ListB     def merge_sort(self, A):    if len(A) == 1: return A    else:        middle = len(A)/2                return self.merge(self.merge_sort(A[:middle]), self.merge_sort(A[middle:]))        def count_inversion(self, sequence):    self.merge_sort(sequence)    return self.count

if name == 'main':
nx()

编橙之家文章，