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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
	int co = 0, N = 0;
	vector<int> c;
	int count = 0;
	for (int i = 0; i < 3; i++) {
		cin >> co;
		c.emplace_back(co);
	}
	sort(c.begin(), c.end());
	cin >> N;
	
	for (int i = 0; i*c[2] <= N; i++) {
		for (int j = 0; j*c[1] + i*c[2] <= N; j++) {
			if ((N - (j*c[1] + i*c[2])) % c[0] == 0) {
				count++;
			}
		}
	}
	cout << count;

	return 0;
}