题解 | #顺时针打印矩阵#

# -*- 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
        res = []
        n = len(matrix)
        if n==0:
            return res
        left = 0
        right = len(matrix[0])-1
        top = 0
        bottom = n-1
        while left<=right and top <=bottom:
            # 上边界从左到右
            for i in range(left,right+1):
                res.append(matrix[top][i])
            # 上边界向下
            top+=1
            if top>bottom:
                break
            # 右边界从上到下
            for i in range(top,bottom+1):
                res.append(matrix[i][right])
            # 右边界向左
            right -=1
            if right < left:
                break
            for i in range(right,left-1,-1):
                res.append(matrix[bottom][i])
            # 下边界向上
            bottom-=1
            if bottom<top:
                break
            # 左边界从下到上
            for i in range(bottom,top-1,-1):
                res.append(matrix[i][left])
            left +=1
            if left>right:
                break
        return res