编辑代码

import java.util.Scanner;
// 1:无需package
// 2: 类名必须Main, 不可修改

public class Main {
    static int ans = 0;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int[] res = new int[]{1,2,3,4,5,6,7,8,9,10,11,12,13};
        f(0,res);
        System.out.println(ans);
        scan.close();
    }
    public static void f(int k,int[] res)
    {
        if(k>12)
        {
            return;
        }
        if(k==13)
        {
            if(check(res))
            {
                ans++;
                return;
            }
        }
        for(int i = k;i<13;i++)
        {
            int temp = res[i];
            res[i] = res[k];
            res[k] = temp;
            if((k==2&&res[0]+res[1]!=res[2])||(k==5&&res[3]-res[4]!=res[5]&&res[0]+res[1]!=res[2])||(k==8&&res[6]*res[7]==res[8]))
            {
                temp = res[k];
                res[k] = res[i];
                res[i] = temp;
                continue;
            }
            f(k+1,res);
            temp = res[k];
            res[k] = res[i];
            res[i] = temp;
        }

    }
    public static boolean check(int[] res)
    {
        boolean match = false;
        if(res[0]+res[1]==res[2]&&res[3]-res[4]==res[5]&&res[6]*res[7]==res[8]&&res[9]==res[10]*res[9])
        {
            match = true;
        }
        return match;
    }
}