Leetcode skimming ---832

subject ： Given a  n x n  The binary matrix of  image , Flip the image horizontally first , Then invert the image and return the result . Flip the picture horizontally is to flip every line of the picture , Reverse order . for example , Flip horizontal  [1,1,0]  The result is  [0,1,1]. Reverse picture means... In picture  0  All by  1  Replace , 1  All by  0  Replace . for example , reverse  [0,1,1]  The result is  [1,0,0].

Input ：image = [[1,1,0],[1,0,1],[0,0,0]]

Output ：[[1,0,0],[0,1,0],[1,1,1]]

Method 1 ： Simulation optimization + Double pointer

class Solution {
public:
    vector<vector<int>> flipAndInvertImage(vector<vector<int>>& image) {
        int n = image.size();
        for (int i = 0; i < n; i++) {
            int left = 0, right = n - 1;
            while (left < right) {
                if (image[i][left] == image[i][right]) {
                    image[i][left] ^= 1;
                    image[i][right] ^= 1;
                }
                left++;
                right--;
            }
            if (left == right) {
                image[i][left] ^= 1;
            }
        }
        return image;
    }
};

Complexity analysis

Time complexity ：O(n^2)

Spatial complexity ：O(1)