Flipping an Image

先左右翻转, 然后0/1互换

class Solution {
    public int[][] flipAndInvertImage(int[][] A) {
        rev(A);
        inv(A);
        return A;
    }
    
    private void inv(int[][] A) {
        for(int i = 0 ; i < A.length; i++) {
            for(int j = 0; j < A[0].length; j++) {
                if(A[i][j] == 0)
                    A[i][j] = 1;
                else
                    A[i][j] = 0;
            }
        }
    }
    
    private void rev(int[][] A) {
        for(int k = 0; k < A.length; k++) {
            swap(A, k);
        }
    }
    
    private void swap(int[][]A, int k) {
        int i = 0;
        int j = A[0].length - 1;
        while(i < j) {
            int t = A[k][i];
            A[k][i] = A[k][j];
            A[k][j] = t;
            i++;
            j--;
        }
    }
}