顺时针打印矩阵 牛客网 剑指Offer

顺时针打印矩阵 牛客网 剑指Offer

• 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.

 

class Solution:
    #run:33ms memory:5712k
    def printMatrix(self, matrix):
        if matrix is None:
            return None
        if matrix is []:
            return []
        r = len(matrix)
        c = len(matrix[0])
        lt = []
        start = 0
        while c > 2 * start and r > 2 * start:
            endX = c - 1 - start
            endY = r - 1 - start
            for i in range(start,endX+1):
                lt.append(matrix[start][i])
            if start < endY:
                for i in range(start+1,endY+1):
                    lt.append(matrix[i][endX])
            if start < endX and start < endY:
                for i in range(endX-1,start-1,-1):
                    lt.append(matrix[endY][i])
            if start < endX and start < endY -1:
                for i in range(endY-1,start,-1):
                    lt.append(matrix[i][start])
            start +=1
        return lt