How to implement majority combination merging in java

package Shuru_lianxi;
 
import java.util.ArrayList;
import java.util.Scanner;
 
public class biShi {
 
	public static boolean isNull(ArrayList<String> gh) {
		int i = 0;
		for (i = 0; i < gh.size(); i++) {
			if (gh.get(i) != null)
				break;
		}
		if (i < gh.size()) {
			return false;
		} else {
			return true;
		}
	}
 
	public static void Alg(ArrayList<String> ma, int num) {
		String tem = "";// 作为最后的返回结果
		while (!isNull(ma)) {
			for (int i = 0; i < ma.size(); i++) {
				String sk = ma.get(i);
				if (sk == null) {
					continue;
				}
				String[] gg = sk.split(",");
				if (sk.length() == 0) {
					ma.set(i, null);// 删掉取完的内容
				} else {
					if (gg.length <= num) {
						tem = tem + sk + ",";
						ma.set(i, null);
					} else {
						for (int k = 0; k < num; k++) {
							tem = tem + gg[k] + ",";
						}
						String hh = "";
						for (int l = num; l < gg.length; l++) {
							if (l == gg.length - 1) {
								hh = hh + gg[l];
							} else {
								hh = hh + gg[l] + ",";
							}
						}
						// 将没取完的数组重新覆盖
						ma.set(i, hh);
					}
				}
			}
		}
		System.out.println(tem.substring(0, tem.length() - 1));
	}
 
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int num = sc.nextInt();
		ArrayList<String> ma = new ArrayList<String>();
		sc.nextLine();// nextInt()会留下一个回车，需要消除,否则后边会出错
		while (!sc.hasNext("#")) {// 以#结束，这里你可以修改成其他的
			ma.add(sc.nextLine());
		}
		Alg(ma, num);
	}
}