10 lines concise C++ solution, recursion.
\nclass Solution {\npublic:\n    bool isValidSerialization(string s) {\n        int idx = 0;\n        return f(s, idx) && idx == s.size();\n    }\n    \n    boo
```\nclass Solution {\npublic:\n    bool isValidSerialization(string s) {\n        int idx = 0;\n        return f(s, idx) && idx == s.size();\n    }\n    \n    bool f(string &s, int &idx) {\n        if(idx >= s.size()) return false;\n        if(s[idx] == \'#\') {\n            idx = min(idx+2, (int)s.size());\n            return true;\n        }\n        while(idx < s.size() && s[idx++] != \',\');\n        return f(s, idx) && f(s, idx);\n    }\n};\n```
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