victor dumitru
victor dumitru

Reputation: 41

Python recursion - max lenght of a subsequence in a matrix is not updated

I am trying to find the longest sequence of a character in a matrix. I am realively new to python, and I think the problem is that python's recursive methods are not the same as C/C++/Java etc. here is my code, now... Do you know another way to do this, if reccursion is not a thing in Python, or can you fix my code to work in pythonic recusion? ( the problem is that the lenght and the visited matrix is not updated during recursion ).

def get_current_score(self, i, j, char, viz, leng):
    leng = 0
    self.viz[i][j] = True

    if (self.out_of_span(i - 1, j) == False and self.viz[i-1][j] == False and self.matrix[i - 1][j] == char):
        self.viz[i - 1][j] = True
        return leng + self.get_current_score(i - 1, j, char, self.viz, leng)
    if (self.out_of_span(i - 1, j +1) == False and self.viz[i-1][j+1] == False and self.matrix[i - 1][j + 1] == char):
        self.viz[i - 1][j + 1] = True
        return leng + self.get_current_score(i - 1, j + 1, char, self.viz, leng)
    if (self.out_of_span(i - 1, j - 1) == False and self.viz[i-1][j-1] == False and self.matrix[i - 1][j - 1] == char):
        self.viz[i - 1][j - 1] = True
        return leng + self.get_current_score(i - 1, j - 1, char, self.viz, leng)
    if (self.out_of_span(i, j - 1) == False and self.viz[i][j-1] == False and self.matrix[i][j - 1] == char):
        self.viz[i][j - 1] = True
        return leng + self.get_current_score(i, j - 1, char, self.viz, leng)
    if ( self.out_of_span(i, j + 1) == False and self.viz[i][j+1] == False and self.matrix[i][j + 1] == char):
        self.viz[i][j + 1] = True
        return leng + self.get_current_score(i, j + 1, char, self.viz, leng)
    if ( self.out_of_span(i + 1, j) == False and self.viz[i+1][j] == False and self.matrix[i + 1][j] == char):
        self.viz[i + 1][j] = True
        return leng + self.get_current_score(i + 1, j, char, self.viz, leng)
    if (self.out_of_span(i + 1, j - 1) == False and self.viz[i+1][j-1] == False and self.matrix[i + 1][j - 1] == char):
        self.viz[i + 1][j - 1] = True
        return leng + self.get_current_score(i + 1, j - 1, char, self.viz, leng)
    if (self.out_of_span(i + 1, j + 1) == False and self.viz[i+1][j+1] == False and self.matrix[i + 1][j + 1] == char):
        self.viz[i + 1][j + 1] = True
        return leng + self.get_current_score(i + 1, j + 1, char, self.viz, leng)

    return 1 + leng

def add(self, index):
    [...]
    # scor
    print('\n --------------\n')
    for i in range(self.maxh, self.nr):
        for j in range(self.span[0], self.span[1]+1):
                if(self.player1 == False and self.matrix[i][j] == 'X'):

                    self.score1 = max(self.score1, self.get_current_score(i, j, 'X', self.viz, self.score1))
                    self.viz[i][j] = True
                    #self.score1 -= 1
                else:
                    if(self.player1 == True and self.matrix[i][j] == 'O'):
                        self.score2 = max(self.score2, self.get_current_score(i, j, 'O', self.viz, self.score1))
                        self.viz[i][j] = True
    self.reset_viz()
    self.print_matrix()

Upvotes: 2

Views: 70

Answers (1)

bobrobbob
bobrobbob

Reputation: 1281

i think this will do

def get_current_score(self, i, j, char, leng):
    # leng = 0 <- don't
    self.viz[i][j] = True  # you set it twice, let's keep that one

    def test_cell(a, b):  # keep it DRY
        return self.out_of_span(a, b) == False \
               and self.viz[a][b] == False \
               and self.matrix[a][b] == char

    cells = [(i - 1, j), (i - 1, j + 1), (i - 1, j - 1), (i, j - 1),
             (i, j + 1), (i + 1, j), (i + 1, j - 1), (i + 1, j + 1)]
    for a, b in cells:
        if test_cell(a, b): 
            # you don't need to set that cell to true since that's the 
            # first thing you do in the function
            # self.viz[a][b] = True
            return leng + self.get_current_score(a, b, char, leng)

    return 1 + leng

def add(self, index):
    [...]
    # scor
    print('\n --------------\n')
    for i in range(self.maxh, self.nr):
        for j in range(self.span[0], self.span[1]+1):
                if(self.player1 == False and self.matrix[i][j] == 'X'):
                    # no need to send self.viz here. same for score2
                    # if you need to set self.score1 to 0 do it here. not in the recursion
                    self.score1 = max(self.score1, self.get_current_score(i, j, 'X', self.score1))
                    self.viz[i][j] = True
                    #self.score1 -= 1
                else:
                    if(self.player1 == True and self.matrix[i][j] == 'O'):
                        self.score2 = max(self.score2, self.get_current_score(i, j, 'O', self.score1))
                        self.viz[i][j] = True
    self.reset_viz()
    self.print_matrix()

Upvotes: 1

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