LeetCode 832. 翻转图像(Flipping an Image) (Swift)

最新推荐文章于 2019-09-06 20:05:27 发布

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本文介绍了一种算法，用于将二进制矩阵水平翻转并进行元素反转。通过遍历矩阵并对每个元素执行异或操作实现，适用于LeetCode上的翻转图像问题。

题目

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].

样例

Example1
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]]

Example2
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]]

说明

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

解题思路

可以遍历二维数组，拿到数组后先进行反转，然后再遍历数组内容进行与1异或(^)

代码

class Solution {
    func flipAndInvertImage(_ A: [[Int]]) -> [[Int]] {
        var nums = A
        for (i, array) in nums.enumerated(){
            for (j, item) in array.reversed().enumerated(){
                nums[i][j] = item ^ 1 // 异或
            }
        }
        return nums
    }
}

题目地址
https://leetcode.com/problems/flipping-an-image/description/