Kyselyt

import java.util.*;
import java.math.BigInteger;

class kyselyt
{
    static long[] in = new long[1001];
    static long[] digitsSum = new long[18];
    static int inputLen;
    static int len;
    static int digitsInNum;
    static int numWithAns;
    static String ans;
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner scanner = new Scanner(System.in);
        inputLen = scanner.nextInt();
        digitsSum[0] = 0;
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i<inputLen; i++) {
            in[i] = scanner.nextLong();
            for(int j = 1; j<18; j++) {
                digitsSum[j] = digitsSum[j-1] + (long)(j*9*Math.pow(10, j-1));
                if(in[i]<=digitsSum[j] && in[i]>digitsSum[j-1]) digitsInNum = j;
            }
            numWithAns = (int)(Math.ceil((in[i]-digitsSum[digitsInNum-1])/(double)digitsInNum)+Math.pow(10, digitsInNum-1)-1);
            ans = Integer.toString(numWithAns);
            sb.append(ans.charAt(ans.length()-1-(numWithAns%digitsInNum)));
            if(i != inputLen-1)sb.append('\n');
        }
        System.out.println(sb.toString());
    }
}

Test 1

Group: 1

Verdict: WRONG ANSWER

Test 2

Group: 2

Verdict: WRONG ANSWER

Test 3

Group: 3

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of...