leetcode

0 class Solution {

1 public:

2 int numberOfBeams(const vector<string>& bank) const {

3 int res = 0, prev = 0;

4 for(const auto& floor: bank) {

5 int cnt = 0;

6 for(const char c: floor) cnt += c == '1';

7 if(cnt) res += cnt * prev, prev = cnt;

8 }

9 return res;

10 }

11 };