LeetCode 832 Flipping an Image

2020/01/11 LeetCode

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LeetCode题解专栏:LeetCode题解
LeetCode 所有题目总结:LeetCode 所有题目总结
大部分题目C++,Python,Java的解法都有。


题目地址:Flipping an Image - LeetCode


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

题目的意思是给定二进制矩阵A,我们水平翻转图像,然后反转它,并返回结果图像。

java代码如下:

class Solution {
    public int[][] flipAndInvertImage(int[][] A) {
        for (int i = 0; i < A.length; i++) {
            for (int j = 0; j < A[i].length / 2; j++) {
                int temp = A[i][j];
                A[i][j] = A[i][A.length - 1 - j];
                A[i][A.length - 1 - j] = temp;
            }
        }

        for (int i = 0; i < A.length; i++) {
            for (int j = 0; j < A[0].length; j++) {
                A[i][j] = A[i][j] == 0 ? 1 : 0;
            }
        }
        return A;
    }
}

Python的解法基本一致,就不贴了。