I just ran into this problem on a test that I had 24 min to solve. I didn't solve it in time. My brain spun to even see the pattern needed beyond getting the max value. So I went and learned the trick online... https://youtu.be/4rin1enhuQQ?si=By2NI2du9ZO6qtf7

https://github.com/SWT92/hackerrank_flipmatrix

My answer seems different from the originator, anyone got 483 the following matrix?

matrix = [[112, 42, 83, 119], [56, 125, 56, 49],[15, 78, 101, 43], [62, 98, 114, 108]]

this problem deep fried my brain

Symmetry: We exploit the symmetry of the 2Nx2N matrix to reduce calculations. Maximum value: For each position inside N x N, we find the maximum among the number and its three symmetric counterparts. Summation: The sum of these maximum values gives us the desired result.

    public static int flippingMatrix(List<List<Integer>> matrix) {
        int n = matrix.get(0).size()/2;
        int result = 0; 
        for(int i = 0; i<n; i++) {
            for(int j = 0; j<n; j++){
                result += Math.max(matrix.get(i).get(j), Math.max(matrix.get(2*n-1-i).get(j),
                Math.max(matrix.get(2*n-1-i).get(2*n-1-j), matrix.get(i).get(2*n-1-j))));
            }
        }
        return result;
    }

def update_location(i,j,location):
    if i == len(location) - 1 and j == len(location) - 1:
    # if i and j == last row and column in location then do nothing
        pass

    elif j == len(location) - 1:  # if j == last index, update next row index 0

        if location[i + 1][0][1] == matrix[i][j + 1]:  # [i+1][0] == next row index 0
            location[i + 1][0][0] = 1
        elif location[i + 1][0][1] == matrix[i][-1 - j]:
            location[i + 1][0][0] = 2
        elif location[i + 1][0][1] == matrix[-1 - i][j + 1]:
            location[i + 1][0][0] = 3
        elif location[i + 1][0][1] == matrix[-1 - i][-1 - j]:
            location[i + 1][0][0] = 4
    else:  # update next j+1
        print('******************')
        print('max = '+ str(location[i][j + 1][1]))
        print(matrix[i][j + 1],matrix[i][-1 - (j+1)],matrix[-1 - i][j + 1],matrix[-1 - i][-1 - (j+1)])
        if location[i][j + 1][1] == matrix[i][j + 1]:
            print('update to 1')
            # if j exceed len(location), go to next i and start j = 0 again
            location[i][j + 1][0] = 1
        elif location[i][j + 1][1] == matrix[i][-1 - (j+1)]: #need to use -(j+1)
            print('update to 2')
            location[i][j + 1][0] = 2
        elif location[i][j + 1][1] == matrix[-1 - i][j + 1]:
            print('choose to 3')
            location[i][j + 1][0] = 3

        elif location[i][j + 1][1] == matrix[-1 - i][-1 - (j+1)]:
            print('update to 4')
            location[i][j + 1][0] = 4
    return location

    #6x6 wrong at 1,1 and 2,1 26 should be 29 and 20 ->23
    #step24 num 20 doing Q4 then update wrong location
    # before step 24 doing Q4
    #step25 num 26 doing Q4 then update wrong location
    # before step 25 doing Q4

    #เข้าเงื่อนไข else แต่ max ไม่ตรงกับ ค่าใน matrix เลยดักไม่ได้

# if max in q1 -> no move
# if max in q2 -> cur box down, max box down, max box left , max box up
# if max in q3 -> cur box right, max box right, max box up, max box left
# if max in q4 -> cur box right, max box up, max box left