Gach

Gacha.java

package org.kirino;

import java.util.HashMap;
import java.util.Map;

import org.apache.commons.math.random.RandomData;
import org.apache.commons.math.random.RandomDataImpl;

public class Gacha {
	public static void main(String[] args) {
		int types = Integer.valueOf(args[0]);
		RandomData randomData = new RandomDataImpl();
		Map<Integer, Integer> archive = new HashMap<Integer, Integer>();
		int cnt = 0;
		while (true) {
			int result = randomData.nextInt(1, types);

			archive.put(result, 1);
			cnt++;

			if (archive.size() == types) {
				break;
			}
		}

		System.out.println(cnt);
	}
}