C++ very easy to Understand | solution using unordered set
```\nclass Solution {\npublic:\n    int countPrefixes(vector& words, string s) {\n        unordered_set st;\n        int size = s.size();\n        for(int i = 0
```\nclass Solution {\npublic:\n    int countPrefixes(vector<string>& words, string s) {\n        unordered_set<string> st;\n        int size = s.size();\n        for(int i = 0;i<size;i++){\n            string temp = "";\n            for(int j = 0;j<=i;j++){\n                temp+=s[j];\n            }\n            st.insert(temp);\n        }\n        int ans = 0;\n        for(int i = 0;i<words.size();i++){\n            if(st.find(words[i])!=st.end())\n                ans++;\n        }\n        return ans;\n    }\n};
['C']