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 <bits/stdc++.h>
using namespace std;
#define ALL(a) (a).begin(), (a).end()
#define SZ(a) int((a).size())
#define LOWB(x) (x & (-x))
#define UNIQUE(a) sort(ALL(a)), (a).erase(unique(ALL(a)), (a).end())
#define INF 1e9
#define INF_LL 4e18
#define rep(i,a,b) for(__typeof(b) i=a; i<(b); ++i)
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};
/*-----------------------------------*/
int r, g, b, n;

int main() {
  cin >> r >> g >> b >> n;
  int res = 0;
  for (int i=0; i*r<=n; i++) {
    for (int j=0; j*g+i*r<=n; j++) {
      if ((n - j*g - i*r) % b == 0)  res++;
    }
  }
  cout << res << endl;
  return 0;
}