cpp easy solution with queue
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\nclass Solution {\npublic:\n    queue<int>ans;\n    Solution(int n, vector<int>& blacklist) {\n\n        set<int> res(blacklist.begin(),blacklist.end());\n        for(int i=0;i<n;i++){\n            if(res.find(i)==res.end()){\n                ans.push(i);\n            }\n            if(ans.size() == 1e5) break; \n        }\n    }\n    \n    int pick() {\n        int f= ans.front();\n        ans.pop();\n        ans.push(f);\n        return f;\n    }\n};\n\n/**\n * Your Solution object will be instantiated and called as such:\n * Solution* obj = new Solution(n, blacklist);\n * int param_1 = obj->pick();\n */\n## please upvote
['Queue', 'C++']