Java || Counter x ASCII
I hope it was clear Don\'t forget to upvote\n\n# Complexity\n- Time complexity:\nO(n)\n\n# Code\n\nclass Solution {\n    public String greatestLetter(String s) 
```I hope it was clear```  ```Don\'t forget to upvote```\n\n# Complexity\n- Time complexity:\nO(n)\n\n# Code\n```\nclass Solution {\n    public String greatestLetter(String s) {\n        boolean[] seen = new boolean[58];\n        for(char ch : s.toCharArray()){\n            seen[ch-65]=true;\n        }\n        for(int i=57; i>31;i--){\n            if(seen[i] && seen[i-32])\n                return (char)(i+33)+"";\n        }\n        return "";\n    }\n}\n```
['Java']