Spiral Order

spiral-matrix.py

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
# pylint: disable=C0111
'''input
3 3
1 2 3
4 5 6
7 8 9
'''


def spiral(n, m, mat):
    nt = (1, 1, 0)
    while True:
        x, y, st = nt
        if mat[x][y] is None:
            return
        print mat[x][y],
        mat[x][y] = None
        if st == 0:
            if mat[x][y + 1] is None:
                nt = (x + 1, y, 1)
            else:
                nt = (x, y + 1, 0)
        elif st == 1:
            if mat[x + 1][y] is None:
                nt = (x, y - 1, 2)
            else:
                nt = (x + 1, y, 1)
        elif st == 2:
            if mat[x][y - 1] is None:
                nt = (x - 1, y, 3)
            else:
                nt = (x, y - 1, 2)
        else:
            if mat[x - 1][y] is None:
                nt = (x, y + 1, 0)
            else:
                nt = (x - 1, y, 3)


def main():
    n, m = map(int, raw_input().split())
    mat = [[None]*(m + 2)]
    for _ in xrange(n):
        mat.append([None])
        mat[-1].extend(map(int, raw_input().split()))
        mat[-1].append(None)
    mat.append([None]*(m + 2))
    spiral(n, m, mat)
    # print mat
    # for x in xrange(1, n + 1):
    #     for y in xrange(1, n + 1):
    #         print mat[x][y]


main()