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: Time Limit Exceeded)

using System;
using static System.Console;
using System.Text;
using System.Linq;
using static System.Math;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.IO;
using System.Diagnostics;

class Program
{
    public static cp alg;
    public static int n;
    public static int[] rgbn;
    public static List<int[]> V;
    static void Main(string[] args)
    {
        alg = new cp();
        //n = alg.inputInt();
        rgbn = alg.inputSplitInt();
        int R = rgbn[0];
        int G = rgbn[1];
        int B = rgbn[2];
        int n = rgbn[3];
        int count = 0;
        for (int r = 0; r <=n; r++)
        {
            if (r * R > n) break;
            for (int g = 0; g <= n; g++)
            {
                if (r * R +g*G> n) break;
                for (int b = 0; b <= n; b++)
                {
                    if (r * R + g * G + b * B == n) count++;
                    if (r * R + g * G + b * B > n) break;
                }
            }
        }

        WriteLine(count);
    }
}

class cp
{

    public cp()
    {
    }
    public int GCD(int a, int b)
    {
        return a % b == 0 ? b : GCD(b, a % b);
    }
    public int LCM(int a, int b)
    {
        return a * b / GCD(a, b);
    }
    public int countChar(string s, string key)
    {
        return s.Length - s.Replace(key, "").Length;
    }
    public string Yn(bool f)
    {
        if (f)
        {
            return "Yes";
        }
        else
        {
            return "No";
        }
    }
    public string YN(bool f)
    {
        if (f)
        {
            return "YES";
        }
        else
        {
            return "NO";
        }
    }
    public string yn(bool f)
    {
        if (f)
        {
            return "yes";
        }
        else
        {
            return "no";
        }
    }
    public void inputSkip()
    {
        ReadLine();
        return;
    }
    public string inputString()
    {
        return ReadLine();
    }
    public string[] inputSplitString()
    {
        return ReadLine().Split();
    }
    public string[] inputLinesString(int len)
    {
        var arr = new string[len];
        for (int a = 0; a < len; a++)
        {
            arr[a] = ReadLine();
        }
        return arr;
    }
    public string[][] inputJaggedArrayString(int len)
    {
        var arr = new string[len][];
        for (int a = 0; a < len; a++)
        {
            arr[a] = ReadLine().Split();
        }
        return arr;
    }
    public int inputInt()
    {
        return int.Parse(ReadLine());
    }
    public int[] inputSplitInt()
    {
        return ReadLine().Split().Select(i => int.Parse(i)).ToArray();
    }
    public int[] inputLinesInt(int len)
    {
        var arr = new int[len];
        for (int a = 0; a < len; a++)
        {
            arr[a] = int.Parse(ReadLine());
        }
        return arr;
    }
    public int[][] inputJaggedArrayInt(int len)
    {
        var arr = new int[len][];
        for (int a = 0; a < len; a++)
        {
            arr[a] = ReadLine().Split().Select(i => int.Parse(i)).ToArray();
        }
        return arr;
    }
    public long inputLong()
    {
        return long.Parse(ReadLine());
    }
    public long[] inputSplitLong()
    {
        return ReadLine().Split().Select(i => long.Parse(i)).ToArray();
    }
    public long[] inputLinesLong(int len)
    {
        var arr = new long[len];
        for (int a = 0; a < len; a++)
        {
            arr[a] = long.Parse(ReadLine());
        }
        return arr;
    }
    public long[][] inputJaggedArrayLong(int len)
    {
        var arr = new long[len][];
        for (int a = 0; a < len; a++)
        {
            arr[a] = ReadLine().Split().Select(i => long.Parse(i)).ToArray();
        }
        return arr;
    }
    public double inputDouble()
    {
        return double.Parse(ReadLine());
    }
    public double[] inputSplitDouble()
    {
        return ReadLine().Split().Select(i => double.Parse(i)).ToArray();
    }
    public double[] inputLinesDouble(int len)
    {
        var arr = new double[len];
        for (int a = 0; a < len; a++)
        {
            arr[a] = double.Parse(ReadLine());
        }
        return arr;
    }
    public double[][] inputJaggedArrayDouble(int len)
    {
        var arr = new double[len][];
        for (int a = 0; a < len; a++)
        {
            arr[a] = ReadLine().Split().Select(i => double.Parse(i)).ToArray();
        }
        return arr;
    }
}