UVA 10327 Java运行时错误

Question

我需要帮助解决这个名为FlipSort的UVA问题。我使用O（nlogn）方法使用反演，测试用例很好。但我不知道为什么我仍然收到RuntimeError。这是我的Java代码。

import java.io.*;
import java.util.*;
import java.math.*;

class Main {

    static int flips = 0;

    public static void main(String... args) throws IOException {
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader in = new BufferedReader(isr);
        String line;
        while ((line = in.readLine()) != null) {
            BigInteger[] numbers = getNumbers(in.readLine());
            String ans = getAns(numbers);
            System.out.println(ans);
        }
    }

    static String getAns(BigInteger[] numbers) {
        flips = 0;
        mergeSort(numbers);
        return "Minimum exchange operations : " + flips;
    }

    static BigInteger[] mergeSort(BigInteger[] numbers) {
        if (numbers.length <= 1) return numbers;
        int n = numbers.length;
        BigInteger[] p1 = mergeSort(subArray(numbers, 0, n/2));
        BigInteger[] p2 = mergeSort(subArray(numbers, n/2, n));
        return merge(p1, p2);
    }

    static BigInteger[] merge(BigInteger[] p1, BigInteger[] p2) {
        BigInteger[] ans = new BigInteger[p1.length+p2.length];
        int i = 0, j = 0, k = 0;
        while (i < p1.length || j < p2.length) {
            if (i < p1.length && j < p2.length) {
                if (p1[i].compareTo(p2[j]) <= 0) {
                    ans[k] = p1[i];
                    i++;
                } else {
                    flips++;
                    ans[k] = p2[j];
                    j++;
                }
            } else if (i < p1.length) {
                ans[k] = p1[i];
                i++;
            } else if (j < p2.length) {
                ans[k] = p2[j];
                j++;
            }
            k++;
        }
        return ans;
    }

    static BigInteger[] subArray(BigInteger[] numbers, int start, int end) {
        BigInteger[] ans = new BigInteger[end-start];
        for (int i = start; i < end; i++)
            ans[i-start] = numbers[i];
        return ans;
    }

    static BigInteger[] getNumbers(String line) {
        String[] vals = line.split(" ");
        BigInteger[] ans = new BigInteger[vals.length];
        for (int i = 0; i < ans.length; i++)
            ans[i] = new BigInteger(vals[i]);
        return ans;
    }
}