Hos' Xmas Contest 2011 H "output"

問題：http://atcoder.jp/problem/detail/139

部分点だけもらえるコード．

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

public class Main {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		String line = s.nextLine();
		if (!s.hasNextLine()) { // BDEFH AC
			if (line.equals("NO")) { // ACD
				System.out.println("ACD");
			} else if (line.matches("\\d+")) { // BEF
				BigInteger n = new BigInteger(line);
				if (n.equals(BigInteger.ZERO)) {
					System.out.println("E");
				} else if (n.equals(BigInteger.ONE)) {
					System.out.println("BE");
				} else if (n.compareTo(BigInteger.valueOf(50)) <= 0) {
					System.out.println("BEF");
				} else if (n.compareTo(BigInteger.valueOf(1000000000)) <= 0) {
					System.out.println("BF");
				} else {
					System.out.println("B");
				}
			} else { // DH
				Set<String> set = new HashSet<String>(Arrays.asList("A", "B", "BE", "BEF", "BF",
						"C", "ACD", "D", "DH", "E", "G"));
				if (set.contains(line)) {
					System.out.println("DH");
				} else {
					System.out.println("D");
				}
			}
		} else { // ACG
			if (s.nextLine().matches("[a-z]+")) {
				System.out.println("A");
			} else if (line.contains(" ")) {
				System.out.println("C");
			} else {
				System.out.println("G");
			}
		}
	}

}