2023.2.1-----leetcode.2325

 public String decodeMessage(String key, String message) {
        int next='a';
        int[] cs=new int[26];
        // int idx=0;
        Arrays.fill(cs,-1);
        for(int i=0;i<key.length();i++){
            if(key.charAt(i)==' ')
                continue;
            if(cs[key.charAt(i)-'a']==-1)
                cs[key.charAt(i)-'a']=next++;
            
        }
        StringBuilder sb=new StringBuilder();
        for(int i=0;i<message.length();i++){
            if(message.charAt(i)==' ')
                sb.append(" ");
            else
                sb.append((char)cs[message.charAt(i)-'a']);
        }
        return sb.toString();
    }