数独

class SudokuCal:
    def __init__(self):
        self.str1 = '0' * 81
        self.str2 = '0' * 81
        self.answer = 0
        self.done = False
        self.loop = 0
    def same_row(self,i,j):
        return (i%9==j%9)
    def same_col(self,i,j):
        return (i-j)%9==0
    def same_block(self,i,j):
        return (i%27%9/3==j%27%9/3)
    def print_format(self,a):
        for i in range(9):
            for j in range(9):
                print '%s' % a[9*i+j]
            print ''

    def r(self,a):
        self.loop += 1
        if(self.answer==1 and self.loop>100000):
            self.done = True
        i = a.find('0')
        if(i==-1):
            self.print_format(a)
            print ''
            self.answer +=1
            if(self.answer==1):
                self.str1=a
                print('loop %d' % self.loop)
            elif(self.answer==2):
                self.str2=a
                self.done=True
                return
        excluded_numbers = set()
        for j in range(81):
            if(self.same_row(i,j) or self.same_col(i,j) or self.same_block(i,j)):
                excluded_numbers.add(a[j])
        for m in '123456789':
            if(m not in excluded_numbers):
                if(self.done):
                    return
                self.r(a[:i] + m + a[i+1:])

a = [8,0,0,0,0,0,0,0,0,
     0,0,3,6,0,0,0,0,0,
     0,7,0,0,9,0,2,0,0,
     0,5,0,0,0,7,0,0,0,
     0,0,0,0,4,5,7,0,0,
     0,0,0,1,0,0,0,3,0,
     0,0,1,0,0,0,0,6,8,
     0,0,8,5,0,0,0,1,0,
     0,9,0,0,0,0,4,0,0]
b = ''.join([str(i) for i in a ])
s = SudokuCal()
s.r(b)
raw_input()