python剑指offer 顺时针打印指针

时间：2023-03-09 13:41:41
python剑指offer 顺时针打印指针

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. 
# -*- 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

        if not matrix:

            return None

        rows = len(matrix)

        cols = len(matrix[0])

        start = 0

        result = []

        while rows > 2*start and cols > 2*start:

            endx = rows-1-start

            endy = cols-1-start

            for i in range(start,endy+1):

                result.append(matrix[start][i])

            if start < endx:

                for i in range(start+1,endx+1):

                    result.append(matrix[i][endy])

            if start < endx and start < endy:

                for i in range(endy-1,start-1,-1):

                    result.append(matrix[endx][i])

            if start < endx-1 and start < endy:

                for i in range(endx-1,start,-1):

                    result.append(matrix[i][start])

            start += 1

        return result

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