Divide a string into the groups of k.
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```\nclass Solution {\npublic:\n    vector<string> divideString(string s, int k, char fill) {\n        int n=s.size();\n        int r=n%k;\n        if (r != 0) {\n            s.append(k - r, fill);\n        }\n        int l=s.size()/k;\n        vector<string> res;\n       for (int i = 0; i < l; ++i) {\n            res.push_back(s.substr(i * k, k));\n        }\n        return res;\n    }\n};\n```
['C++']