✅C++ | Backtracking- recursion | Easy to Understand
\nclass Solution {\npublic:\n    \n    void helper(int n, vector<char> &temp,int &count, int idx, vector<char> &vowels)\n    {\n        if(temp.size()==n)\n    
```\nclass Solution {\npublic:\n    \n    void helper(int n, vector<char> &temp,int &count, int idx, vector<char> &vowels)\n    {\n        if(temp.size()==n)\n        {\n            count++;\n            return;\n        }\n        \n        for(int i=idx; i<vowels.size(); i++)\n        {\n            temp.push_back(vowels[i]);\n            helper(n, temp, count, i, vowels);\n            temp.pop_back();\n        }\n        return;\n    }\n    \n    int countVowelStrings(int n) \n    {\n        vector<char> vowels{\'a\',\'e\',\'i\',\'o\',\'u\'};\n        int count=0;\n        vector<char> temp;\n        helper(n, temp, count, 0, vowels);\n        return count;        \n    }\n};\n```
['Backtracking', 'Recursion', 'C', 'C++']