Flipping an Image

最新推荐文章于 2025-09-12 00:40:07 发布

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原文链接：http://www.cnblogs.com/locke-hu/p/9628364.html

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#人工智能 #python

本文介绍了一种处理二进制矩阵的算法，该算法首先将矩阵中的每一行进行水平翻转，然后对所有元素进行取反操作，即将0变为1，1变为0，并通过Python实现。

Given a binary matrix A, we want to flip the image horizontally, then invert it, and return the resulting image.

To flip an image horizontally means that each row of the image is reversed. For example, flipping [1, 1, 0] horizontally results in [0, 1, 1].

To invert an image means that each 0 is replaced by 1, and each 1 is replaced by 0. For example, inverting [0, 1, 1] results in [1, 0, 0].

Example 1:

Input: [[1,1,0],[1,0,1],[0,0,0]]
Output: [[1,0,0],[0,1,0],[1,1,1]]
Explanation: First reverse each row: [[0,1,1],[1,0,1],[0,0,0]].
Then, invert the image: [[1,0,0],[0,1,0],[1,1,1]]

Example 2:

Input: [[1,1,0,0],[1,0,0,1],[0,1,1,1],[1,0,1,0]]
Output: [[1,1,0,0],[0,1,1,0],[0,0,0,1],[1,0,1,0]]
Explanation: First reverse each row: [[0,0,1,1],[1,0,0,1],[1,1,1,0],[0,1,0,1]].
Then invert the image: [[1,1,0,0],[0,1,1,0],[0,0,0,1],[1,0,1,0]]

Notes:

1 <= A.length = A[0].length <= 20
0 <= A[i][j] <= 1

Python3

 1 class Solution:
 2     def flipAndInvertImage(self, A):
 3         """
 4         :type A: List[List[int]]
 5         :rtype: List[List[int]]
 6         """
 7         return [[1-i for i in row[::-1]] for row in A]
 8     
 9         # 0. 过程分析
10         # 1. 先对A进行反向切片A[::-1]
11         # 2. 1-i可以达到取反的目的
12         # 3. 取反也可以使用位异或运算符1^i
13             # 3.1 1二进制为 0001
14             # 3.2 0二进制为 0000
15             # 3.3 1^0为 0001,十进制为1
16             # 3.4 1^1为 0000，十进制为0
17             # 3.5 则达到了0变1,1变0取反的目的