【模拟】1576. 替换所有的问号

class Solution {
    public String modifyString(String s) {
        
        char[] ret=s.toCharArray();
        int n=s.length();
        for(int i=0;i<n;i++){
            if(ret[i]=='?'){
               for(char newchar='a';newchar<='z';newchar++){
                    if((i==0||newchar!=ret[i-1]) &&(i==n-1||newchar!=ret[i+1])){
                        ret[i]=newchar;
                        break;
                    }
            }
           
        }
         
        
    }
    return String.valueOf(ret);
}
}