1576. Replace All ?'s to Avoid Consecutive Repeating Characters

Runtime    1 ms
Beats      100%


Memory     41.4 MB
Beats      72.58%


class Solution {
    public String modifyString(String s) {
        if(s.length()==1) return s.equals("?")?"a":s;

        char[] ch = s.toCharArray();
        for(int i=1;i<ch.length-1;i++){
            if(ch[i]=='?'){
                if(ch[i-1]!='a' && ch[i+1]!='a') ch[i]='a';
                else if(ch[i-1]!='b' && ch[i+1]!='b') ch[i]='b';
                else if(ch[i-1]!='c' && ch[i+1]!='c') ch[i]='c';
            }
        }


        if(ch[0]=='?')
            ch[0]=ch[1]=='a'?'b':'a';

        if(ch[ch.length-1]=='?')
            ch[ch.length-1]=ch[ch.length-2]=='a'?'b':'a';

        return new String(ch);
    }
}