Problem p03048 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(j, n) for (int j = 0; j < (n); ++j)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define drep2(j, n) for (int j = (n)-1; j >= 0; --j)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define srep2(j, s, t) for (int j = s; j < t; ++j)
#define srep3(k, s, t) for (int k = s; k < t; ++k)
#define rng(a) a.begin(), a.end()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define snuke srand((unsigned)clock() + (unsigned)time(NULL));
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef set<int> S;
typedef queue<int> Q;
typedef queue<P> QP;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame                                                                   \
  {                                                                            \
    puts("-1");                                                                \
    return 0;                                                                  \
  }
#define yn                                                                     \
  { puts("YES"); }                                                             \
  else {                                                                       \
    puts("NO");                                                                \
  }

int R, G, B, N;

int main() {

  cin >> R >> G >> B >> N;
  int ans = 0;
  int Rlim = N / R;
  int Glim = N / G;
  int Blim = N / B;
  rep(i, Rlim + 1) {
    if (R * i > N)
      continue;
    rep(j, Glim + 1) {
      if (R * i + G * j > N)
        continue;
      rep(k, Blim + 1) {
        if (R * i + G * j + B * k == N) {
          ans++;
        }
      }
    }
  }
  cout << ans << endl;
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(j, n) for (int j = 0; j < (n); ++j)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define drep2(j, n) for (int j = (n)-1; j >= 0; --j)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define srep2(j, s, t) for (int j = s; j < t; ++j)
#define srep3(k, s, t) for (int k = s; k < t; ++k)
#define rng(a) a.begin(), a.end()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define snuke srand((unsigned)clock() + (unsigned)time(NULL));
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef set<int> S;
typedef queue<int> Q;
typedef queue<P> QP;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
inline int in() {
  int x;
  scanf("%d", &x);
  return x;
}
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame                                                                   \
  {                                                                            \
    puts("-1");                                                                \
    return 0;                                                                  \
  }
#define yn                                                                     \
  { puts("YES"); }                                                             \
  else {                                                                       \
    puts("NO");                                                                \
  }

int R, G, B, N;

int main() {

  cin >> R >> G >> B >> N;
  int ans = 0;
  int Rlim = N / R;
  int Glim = N / G;
  int Blim = N / B;
  rep(i, Rlim + 1) {
    if (R * i > N)
      continue;
    rep(j, Glim + 1) {
      if (R * i + G * j > N)
        continue;
      int diff = N - (R * i + G * j);
      if (diff < 0)
        continue;
      if (diff % B == 0 || diff == 0)
        ans++;
    }
  }
  cout << ans << endl;
  return 0;
}