very Easy to understand Solution
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```java []\nclass Solution {\n    public String[] divideString(String s, int k, char fill) {\n        int size = (s.length() + k - 1) / k; // Correct array size\n        String[] res = new String[size];\n        \n        int i = 0;\n        int index = 0;\n        \n        while (i < s.length()) {\n            if (i + k <= s.length()) {\n                // If enough characters remain for a full group\n                res[index++] = s.substring(i, i + k);\n            } else {\n                // If the remaining characters are less than k, fill with \'fill\' char\n                StringBuilder sb = new StringBuilder(s.substring(i));\n                while (sb.length() < k) {\n                    sb.append(fill);\n                }\n                res[index++] = sb.toString();\n            }\n            i += k;\n        }\n        \n        return res;\n    }\n}\n\n```
['Java']