백준 자바 10809 문자열(알파벳찾기

https://www.acmicpc.net/problem/10809

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String word = br.readLine();

        int [] arr = new int[26];
        for(int i=0; i<arr.length; i++){
            arr[i] = -1;
        }
        for(int i=0; i<word.length(); i++){
            char ch = word.charAt(i);
            if(arr[ch-'a'] == -1){
                arr[ch-'a'] = i;
            }
        }
        for(int val : arr){
            System.out.print(val + " ");
        }
    }
}https://www.acmicpc.net/problem/10809