'''
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.
'''

# -*- coding:utf-8 -*-
class Solution:
    # matrix类型为二维列表，需要返回列表
    def printMatrix(self, matrix):
        # write code here
        rows = len(matrix)
        cols = len(matrix[0])
        result = []
        if rows == 0 and cols == 0:
            return result
        left, right, top, buttom = 0, cols-1, 0, rows-1
        while left <= right and top <= buttom:
            for i in range(left, right+1):
                result.append(matrix[top][i])
            for i in range(top+1, buttom+1):
                result.append(matrix[i][right])
            if top != buttom:
                for i in range(left, right)[::-1]:
                    result.append(matrix[buttom][i])
            if left != right:
                for i in range(top+1, buttom)[::-1]:
                    result.append(matrix[i][left])
            left += 1
            right -= 1
            top += 1
            buttom -= 1
        return result


