java easy 1 ms, faster than 100.00%
public String modifyString(String s) {\n        StringBuilder sb = new StringBuilder();\n        for(int i = 0; i < s.length(); i++){\n            if(s.charAt(i
public String modifyString(String s) {\n        StringBuilder sb = new StringBuilder();\n        for(int i = 0; i < s.length(); i++){\n            if(s.charAt(i) == \'?\'){\n                char ch = \'a\';\n                while((i != 0 && sb.charAt(i-1) == ch) || (i != s.length() - 1 && s.charAt(i+1)                   == ch))ch++;\n                sb.append(ch);    \n            }\n            else\n              sb.append(s.charAt(i));    \n        } \n        return sb.toString();\n    }
[]