ブルーブリッジカップ - 配列要素ゼロ（Javaの）削除する学習アルゴリズム

import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int len = sc.nextInt();
		int[] nums = new int[len];
		for(int i = 0;i < nums.length;i++) {
			nums[i] = sc.nextInt();
		}
		int count = CompactIntegers(nums, nums.length);
		int[] res = new int[count];
		int index = 0;
		for(int i = 0;i < nums.length;i++) {
			if(nums[i] != 0) {
				res[index++] = nums[i];
			}
		}
		System.out.println(count);
		for(int x : res) {
			System.out.print(x + " ");
		}
		sc.close();
	}
	
	public static int CompactIntegers(int[] nums, int count) {
		for(int i = 0;i < nums.length;i++) {
			if(nums[i] == 0) count--;
		}
		return count;
	}
}