gistfile1.txt

public static List<int[][]> interpret(String path) {
        List<int[][]> ret = new ArrayList<>();
        
        try {
            File file = new File(path);
            BufferedReader reader = new BufferedReader(new FileReader(file));
            
            String s;
            while((s = reader.readLine()) != null) {
                s = s.trim();
                
                if (!s.isEmpty()) {
                    int maxSize = (int)Math.sqrt(s.length());
                    int[][] grid = new int[maxSize][maxSize];
                    for(int i = 0; i < s.length(); i++) {
                        char c = s.charAt(i);
                        int val = c == '.' ? 0 : Integer.parseInt(Character.toString(c));
                        grid[i/maxSize][i%maxSize] = val;
                    }
                    ret.add(grid);
                }
            }
            
            reader.close();
        } catch(Exception e) {
            e.printStackTrace();
        }
        
        return ret;
    }