# 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
}