c++ hash table
c++\nclass Solution {\npublic:\n    int maximumNumberOfStringPairs(vector<string>& words) {\n        unordered_set<string> us;\n        int res = 0;\n        fo
```c++\nclass Solution {\npublic:\n    int maximumNumberOfStringPairs(vector<string>& words) {\n        unordered_set<string> us;\n        int res = 0;\n        for(auto w : words) {\n            if(us.count(w)) res += 1;\n            reverse(begin(w), end(w));\n            us.insert(w);\n        }\n        return res;\n    }\n};\n\n```
[]