leetcode

0 class Solution {

1 typedef bitset<512> bs_t;

2

3 public:

4 int maxEqualRowsAfterFlips(const vector<vector<int>> &matrix) {

5 int n = matrix.size(), m = matrix[0].size(), res = 0;

6 unordered_map<bs_t, int> um;

7 for (int i = 0; i < n; i++) {

8 bs_t crnt;

9 for (int j = 0; j < m; j++)

10 crnt[j] = matrix[i][j] != matrix[i][0];

11 res = max(res, ++um[crnt]);

12 }

13 return res;

14 }

15 };