C++ Concise 100%
class Solution {\npublic:\n    string smallestSubsequence(string text) {\n        \n        string str="";\n        vector count(26,0);\n        vector used(26,
class Solution {\npublic:\n    string smallestSubsequence(string text) {\n        \n        string str="";\n        vector<int> count(26,0);\n        vector<bool> used(26,false);\n        for (auto i:text)\n            count[i-\'a\']++;\n        \n        for (auto i:text)\n            {\n                count[i-\'a\']--;\n\n                if(used[i-\'a\']==false)\n                {\n\n                while (str.length()>0 && i<str.back() && count[str.back()-\'a\']>0)\n                    {\n                        used[str.back()-\'a\']= false;\n                        str.pop_back();\n                    }\n\n                str.push_back(i);\n                used[i-\'a\']= true;\n                }\n\n            }\n\n        return str;\n    }\n};
['C', 'C++']