angry-children.java

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'maxMin' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts following parameters:
     *  1. INTEGER k
     *  2. INTEGER_ARRAY arr
     */

    public static int maxMin(int k, List<Integer> arr) {
        Collections.sort(arr);
        System.out.println(arr);
        int tmp = 0, max = 0, min = 0,
            result = Integer.MAX_VALUE;

        for (int x = k - 1; x < arr.size(); x++) {
            max = arr.get(x);
            min = arr.get(x - k + 1);
            tmp = max - min;
            if (result > tmp) {
                result = tmp;
            }
        }

        return result;
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = Integer.parseInt(bufferedReader.readLine().trim());

        int k = Integer.parseInt(bufferedReader.readLine().trim());

        List<Integer> arr = IntStream.range(0, n).mapToObj(i -> {
            try {
                return bufferedReader.readLine().replaceAll("\\s+$", "");
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        })
            .map(String::trim)
            .map(Integer::parseInt)
            .collect(toList());

        int result = Result.maxMin(k, arr);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}