TBC

https://leetcode.com/contest/biweekly-contest-54/problems/largest-magic-square/
class Solution {

public:
    int largestMagicSquare(vector<vector<int>>& grid) {

        using Matrix = std::vector<std::vector<long long>>;

        Matrix row_sum(grid.size(), std::vector<long long>(grid[0].size(), 0));
        Matrix col_sum(grid.size(), std::vector<long long>(grid[0].size(), 0));
        Matrix p_diag_sum(grid.size(), std::vector<long long>(grid[0].size(), 0));
        Matrix s_diag_sum(grid.size(), std::vector<long long>(grid[0].size(), 0));

        row_sum[0][0] = grid[0][0];
        col_sum[0][0] = grid[0][0];
        p_diag_sum[0][0] = grid[0][0];
        s_diag_sum[0][0] = grid[0][0];


        // first row
        for(int i = 1; i < grid[0].size(); ++i) {
            row_sum[0][i] = row_sum[0][i-1] + grid[0][i];
        }

        // first col
        for(int i = 1; i < grid.size(); ++i) {
            row_sum[i][0] = row_sum[i-1][0] + grid[i][0];
        }

        for(int i = 1; i < grid.size(); ++i) {
            for(int j = 1; j < grid[0].size(); ++j) {
                row_sum[i][j] = row_sum[i][j-1] + grid[i][j];
                col_sum[i][j] = col_sum[i-1][j] + grid[i][j];
                p_diag_sum[i][j] = p_diag_sum[i-1][j-1] + grid[i][j];
                s_diag_sum[i][j] =
            }
        }

        int max_size = std::min(grid.size(), grid[0].size());
        for(int sq_size = max_size; sq_size > 0; --sq_size) {
            for(int top_left_r = 0; top_left_r + max_size < grid.size(); ++top_left_r) {
                for(int top_left_c = 0; top_left_c + max_size < grid[0].size(); ++top_left_c) {



                }
            }
        }

    }
};