832. Flipping an Image

Easy

Given an n x n binary matrix image, 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: image = [[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: image = [[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]]

Constraints:

• n == image.length

• n == image[i].length

• 1 <= n <= 20

• images[i][j] is either 0 or 1.

解題

Runtime: 0 ms, faster than 100.00%

Memory Usage: 2.9 MB, less than 77.39%

func flipAndInvertImage(image [][]int) [][]int {
    for _, line := range image {
        left, right := 0, len(line)-1
        
        for left <= right {
            if line[left]==line[right] {
                line[left] = invert(line[left]) 
                line[right] = line[left]
            } 
            
            right--
            left++
        }
    }
    
    return image
}

func invert(n int) int {
    if n==1 { return 0 }
    return 1
}