Задача про массивы

#!/usr/bin/env python
#-*- coding: utf8 -*-
 
import sys
 
 
def spiral_gen(start_cell, max_cell, walk_order):
 
    def move(pos, dif):
        return (pos[0] + dif[0], pos[1] + dif[1])
 
    pos = (start_cell, start_cell)
 
    cells_total = max_cell ** 2
    cells_curr = 0
    direction  = 0
 
    cols_visited = [start_cell,]
    rows_visited = [start_cell,]
 
    while cells_curr < cells_total:
        cells_curr += 1
        yield pos
        pos = move(pos, walk_order[direction])
        if (pos[0] not in rows_visited) or (pos[1] not in cols_visited):
            if pos[0] not in rows_visited:
                rows_visited.append(pos[0])
            elif pos[1] not in cols_visited:
                cols_visited.append(pos[1])
 
            direction += 1
            if direction == len(walk_order):
                direction = 0
 
 
def print_matrix(matrix, item_format='{:03}'):
    print '\n'.join([' '.join(map(lambda a: item_format.format(a), row)) for row in matrix])
 
 
def main(args):
    n = int(raw_input('n: '))
    n_max = 2 * n + 1
 
    A = [[0 for col in xrange(n_max)] for row in xrange(n_max)]
    val = 0
 
    ccw = (
        (-1, 0),  # up
        (0, -1),  # left
        (1,  0),  # down
        (0,  1)   # right
    )
 
    for row, col in spiral_gen(n, n_max, ccw):
        A[row][col] = val
        val += 1
    print_matrix(A, '{:02}')
    return 0
 
 
if __name__ == "__main__":
    sys.exit(main(sys.argv))

n=eval(input('Input n:'))
 
array=[]
for i in range(2*n+1):
    array.append([])
    for j in range(2*n+1):
        array[i].append(0)
print(array)
 
add_num=(2*n+1)**2-1
for i in range(0,n):
    for j in range(i,2*n+1-i):
        array[j][2*n-i]=add_num
        add_num-=1
    for j in range(i,2*n-i):
        array[2*n-i][2*n-1-j]=add_num
        add_num-=1
    for j in range(i,2*n-i):
        array[2*n-1-j][i]=add_num
        add_num-=1
    for j in range(i,2*n-i-1):
        array[i][j+1]=add_num
        add_num-=1
 
for i in range(len(array)):
    for j in range(len(array)):
        print(array[i][j],' ',end='')
    print('\n')