6. <Important> Flipping an Image

Title:

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]]

Note:

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

Analysis of Title:

Title is clear.

Test case:

[[1,1,0],[1,0,1],[0,0,0]]

Python:

class Solution(object):
  def flipAndInvertImage(self, A):
  """
  :type A: List[List[int]]
  :rtype: List[List[int]]
  """

  return [[j^1 for j in i[::-1]] for i in A]

Analysis of Code:

Very clever! It use the XOR which I never mind.

Node:Related explanations are in the pycharm.

原文地址:https://www.cnblogs.com/sxuer/p/10629023.html