C++ O(n) 0ms solution
\nclass Solution {\npublic:\n    string modifyString(string s) {\n        for(int i=0; i<s.size(); ++i)\n        {\n            if(s[i]==\'?\')\n            {\n
```\nclass Solution {\npublic:\n    string modifyString(string s) {\n        for(int i=0; i<s.size(); ++i)\n        {\n            if(s[i]==\'?\')\n            {\n                s[i]=\'a\';\n                while((i>0 && s[i]==s[i-1]) || ((i+1)<s.size() && s[i]==s[i+1]))\n                {\n                     s[i]++;\n                }\n            }\n        }\n        return s;\n    }\n};\n```
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