滴滴0928笔试，第一题只过了55%

import java.util.*;
public class Main {
    static int n;
    static HashSet<String> hashSet = new HashSet<>();
    static HashSet<String> ans = new HashSet<>();
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        n = in.nextInt();
        int a = in.nextInt();
        int b = in.nextInt();
        int c = in.nextInt();
        cut(a, b, c, 1);
        System.out.println(ans.size());
    }

    public static void cut(int a, int b, int c, int now) {//剩余now次
        if ( a <= 0 || b <= 0 || c <= 0 || now >n || hashSet.contains(a+","+b+","+c)) {
            return;
        }
        hashSet.add(a+","+b+","+c);
        if (a + b > c && a + c > b && b + c > a) {
            ans.add(a+","+b+","+c+","+now);
        }
        cut(a - now, b, c, now + 1);
        cut(a, b - now, c, now + 1);
        cut(a, b, c - now, now + 1);
    }

}

一份只过了55%的代码，有大佬帮忙分享一下解题思路吗