顺时针打印矩阵

题目描述
输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，例如，如果输入如下4 X 4矩阵： 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.

python solution:

# -*- coding:utf-8 -*-
class Solution:
    # matrix类型为二维列表，需要返回列表
    def printMatrix(self, matrix):
        a,b,c,d = 0,0,len(matrix),len(matrix[0])
        res = [matrix[0][0]]
        dir = 0
        i,j = 0,0
        while len(res)<(len(matrix)*len(matrix[0])):
            if dir == 0: #从左向右走
                while j<d-1:
                    j += 1
                    # print(matrix[i][j])
                    res.append(matrix[i][j])
                a += 1
                dir = 1
                continue
            if dir == 1: #从上向下走
                while i+1<c:
                    i += 1
                    # print(matrix[i][j])
                    res.append(matrix[i][j])
                d -= 1
                dir = 2
                continue
            if dir == 2: #从右向左走
                while j-1>=b:
                    j -= 1
                    # print(matrix[i][j])
                    res.append(matrix[i][j])
                c -= 1
                dir = 3
                continue
            if dir == 3: #从下向上走
                while i-1>=a:
                    i -= 1
                    # print(matrix[i][j])
                    res.append(matrix[i][j])
                b += 1
                dir = 0
                continue
        return res