2125. Number of Laser Beams in a Bank

//https://leetcode.com/problems/number-of-laser-beams-in-a-bank/description/?envType=daily-question&envId=2024-01-03

class Solution {
    public int numberOfBeams(String[] bank) {
         int c = 0, res = 0,ans = 0;
         for(String str : bank){
            c=0;
            for(int j=0;j<str.length();j++)
                if(str.charAt(j) == '1') c++;
             
            if(c!=0){
                ans += c*res;
                res = c;
            }
         }
         
         return ans;
    }
}