Largest Submatrix with Rearrangements

//https://leetcode.com/problems/largest-submatrix-with-rearrangements/

class Solution {
    bool CustomComparator(const std::vector<int> & a, const std::vector<int> & b) {
        bool result = true;
        for(int i = 0;  i < a.size(); ++i) {
            if(a[i] > b[i]) {
                result = false;
                break;
            }
        }
        return result;
    }
public:
    int largestSubmatrix(vector<vector<int>>& matrix) {
        for(int i = 0; i < matrix[0].size(); ++i) {
            int sum = 0;
            for(int j = 0; j < matrix.size(); ++j) {
                sum =  (matrix[j][i] == 0) ? 0  : (sum + 1);
                //std::cout << matrix[j][i] << ",";
                matrix[j][i] = sum;
                //std::cout << sum << "    ";
            }
            //std::cout << "\n";
        }

        int ans = 0;
        for(int i= 0; i < matrix.size(); ++i) {
            // sort the current in descending order
            std::sort(matrix[i].begin(), matrix[i].end() , std::greater<int>());

            for(int j = 0; j < matrix[i].size(); ++j) {
                ans = std::max(ans, matrix[i][j] * (j+1));
            }
        }


        return ans;
    }
};