Problem:
Score : 200 points

Problem Statement

Snuke has come to a store that sells boxes containing balls. The store sells the following three kinds of boxes:

Red boxes, each containing R red balls

Green boxes, each containing G green balls

Blue boxes, each containing B blue balls

Snuke wants to get a total of exactly N balls by buying r red boxes, g green boxes and b blue boxes.
How many triples of non-negative integers (r,g,b) achieve this?

Constraints

All values in input are integers.

1 \leq R,G,B,N \leq 3000

Input

Input is given from Standard Input in the following format:

R G B N

Output

Print the answer.

Sample Input 1

1 2 3 4

Sample Output 1

4

Four triples achieve the objective, as follows:

(4,0,0)

(2,1,0)

(1,0,1)

(0,2,0)

Sample Input 2

13 1 4 3000

Sample Output 2

87058

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace div2019a
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] s = Console.ReadLine().Split(' ');
            int R = int.Parse(s[0]);
            int G = int.Parse(s[1]);
            int B = int.Parse(s[2]);
            int N = int.Parse(s[3]);

            int i, j, k;
            int aa, bb, cc;

            if(R >= G && G >= B)
            {
                aa = R; bb = G; cc = B;

            }else if(G >= R && R >= B)
            {
                aa = G;bb = R;cc = B;
            }else if (B >= R && R >= G)
            {
                aa = B;bb = R;cc = G;
            }else if (R >= B && B >= G)
            {
                aa = R;bb = B;cc = G;
            }else if (G >= B && B >= R)
            {
                aa = G;bb = B;cc = R;
            }else if (B >= G && G >= R)
            {
                aa = B;bb = G;cc = R;
            }
            else
            {

                aa = R; bb = G; cc = B;

            }

            int count = 0;

            for (i = 0; i < (N / aa )+1; i++)
            {
                for (j = 0; j < (N / bb)+1; j++)
                {
                    if ((i * aa + j * bb) > N)
                    {
                        break;
                    }
                    if ((N - (i * aa + j * bb)) % cc == 0)
                    {
                        count++;
                    }


                }
            }

            Console.WriteLine(count);
            Console.ReadLine();

        }
    }
}