C++ 100% Faster
\nclass Solution {\npublic:\n    string modifyString(string s) {\n        int i,n=s.size();\n        for(i=0;i<n;i++){\n            if(s[i]==\'?\'){\n          
```\nclass Solution {\npublic:\n    string modifyString(string s) {\n        int i,n=s.size();\n        for(i=0;i<n;i++){\n            if(s[i]==\'?\'){\n                s[i]=\'a\';\n                while((i>0 && s[i]==s[i-1]) || (i+1<n && s[i]==s[i+1])) s[i]++;\n            }\n        }\n        return s;\n    }\n};\n```
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