鸡兔同笼算法

package com.company;


import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    static final int drumstick = 2;
    static final int rubbitleg = 4;
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int n,i,j;
        int x,y;
        ArrayList
 
   a = new ArrayList
  
   (); n = scan.nextInt(); for(i=0;i