Java- Easy Solution
\nclass Solution {\n    public String modifyString(String s) {\n        char[] str = s.toCharArray();\n        for(int i =0; i < str.length; i ++)\n        {\n 
```\nclass Solution {\n    public String modifyString(String s) {\n        char[] str = s.toCharArray();\n        for(int i =0; i < str.length; i ++)\n        {\n            if(str[i] == \'?\')\n            {\n                str[i] = replaceChar(str, i);\n            }\n        }\n        return String.valueOf(str);\n    }\n    \n    private char replaceChar(char[] s, int i)\n    {\n        for(char ch= \'a\'; ch <= \'z\'; ch++)\n        {\n            if(i > 0 && ch== s[i -1])\n            {\n                continue;\n            }\n            if(i < s.length -1 && ch== s[i + 1])\n            {\n                continue;\n            }\n            return ch;\n        }\n        return 0;\n    }\n}\n```
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