Problem p02623 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define fi first
#define se second
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define eb emplace_back
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define SZ(x) (int)(x).size()
#define endl '\n'
#define FOR(a, b, c) for (auto a = (b); (a) < (c); ++(a))
#define F0R(a, b) FOR(a, 0, (b))
#define CEIL(a, b) ((a) + (b)-1) / (b)
template <class T> bool ckmin(T &a, const T &b) {
  return a > b ? a = b, true : false;
}
template <class T> bool ckmax(T &a, const T &b) {
  return a < b ? a = b, true : false;
}
#ifndef DEBUG
#define DEBUG 0
#endif
#define dout                                                                   \
  if (DEBUG)                                                                   \
  std::cerr
#define dvar(...) " [" << #__VA_ARGS__ ": " << mt(__VA_ARGS__) << "] "
template <typename T> struct IsC {
  template <typename C> static char test(typename C::const_iterator *);
  template <typename C> static int test(...);
  static const bool value = sizeof(test<T>(0)) == sizeof(char);
};
template <> struct IsC<string> {
  static const bool value = false;
};
template <typename C>
typename enable_if<IsC<C>::value, ostream &>::type operator<<(ostream &,
                                                              const C &);
template <typename T1, typename T2>
ostream &operator<<(ostream &, const pair<T1, T2> &);
template <typename... T> using TS = tuple_size<tuple<T...>>;
template <size_t idx, typename... T>
typename enable_if<TS<T...>::value == idx + 1, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return o << ", " << get<idx>(t) << ')';
}
template <size_t idx, typename... T>
typename enable_if<0 < idx && idx + 1 < TS<T...>::value, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return operator<< <idx + 1>(o << ", " << get<idx>(t), t);
}
template <size_t idx = 0, typename... T>
typename enable_if<1 < TS<T...>::value && !idx, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return operator<< <idx + 1>(o << '(' << get<idx>(t), t);
}
template <typename T> ostream &operator<<(ostream &o, const tuple<T> &t) {
  return o << get<0>(t);
}
template <typename T1, typename T2>
ostream &operator<<(ostream &o, const pair<T1, T2> &p) {
  return o << mt(p.fi, p.se);
}
template <typename C>
typename enable_if<IsC<C>::value, ostream &>::type operator<<(ostream &o,
                                                              const C &c) {
  o << '[';
  for (auto it = c.cbegin(); it != c.cend(); ++it)
    o << *it << (next(it) != c.cend() ? ", " : "");
  return o << ']';
}
template <typename T>
void tprint(vector<vector<T>> &v, size_t width = 0, ostream &o = cerr) {
  if (!DEBUG)
    return;
  for (auto &vv : v) {
    for (auto &i : vv)
      o << setw(width) << i;
    o << endl;
  }
}

void solve() {
  int n, m;
  ll k;
  cin >> n >> m >> k;
  vector<ll> as(n), bs(n);
  F0R(i, n) {
    cin >> as[i];
    if (i)
      as[i] += as[i - 1];
  }
  F0R(i, m) {
    cin >> bs[i];
    if (i)
      bs[i] += bs[i - 1];
  }
  dout << dvar(as) << dvar(bs) << endl;
  int best = 0;
  F0R(i, n) {
    if (as[i] > k)
      break;
    int bi = distance(bs.begin(), upper_bound(ALL(bs), k - as[i]));
    dout << dvar(i, bi) << endl;
    ckmax(best, i + 1 + bi);
  }
  F0R(i, m) {
    if (bs[i] > k)
      break;
    int ai = distance(as.begin(), upper_bound(ALL(as), k - bs[i]));
    dout << dvar(i, ai) << endl;
    ckmax(best, i + 1 + ai);
  }
  cout << best << endl;
}

int main() {
  ios_base::sync_with_stdio(0);
  cout.tie(0);

  int tt = 1;
  FOR(t, 1, tt + 1) {
    // cout << "Case #" << t << ": ";
    solve();
  }

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define fi first
#define se second
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define eb emplace_back
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define SZ(x) (int)(x).size()
#define endl '\n'
#define FOR(a, b, c) for (auto a = (b); (a) < (c); ++(a))
#define F0R(a, b) FOR(a, 0, (b))
#define CEIL(a, b) ((a) + (b)-1) / (b)
template <class T> bool ckmin(T &a, const T &b) {
  return a > b ? a = b, true : false;
}
template <class T> bool ckmax(T &a, const T &b) {
  return a < b ? a = b, true : false;
}
#ifndef DEBUG
#define DEBUG 0
#endif
#define dout                                                                   \
  if (DEBUG)                                                                   \
  std::cerr
#define dvar(...) " [" << #__VA_ARGS__ ": " << mt(__VA_ARGS__) << "] "
template <typename T> struct IsC {
  template <typename C> static char test(typename C::const_iterator *);
  template <typename C> static int test(...);
  static const bool value = sizeof(test<T>(0)) == sizeof(char);
};
template <> struct IsC<string> {
  static const bool value = false;
};
template <typename C>
typename enable_if<IsC<C>::value, ostream &>::type operator<<(ostream &,
                                                              const C &);
template <typename T1, typename T2>
ostream &operator<<(ostream &, const pair<T1, T2> &);
template <typename... T> using TS = tuple_size<tuple<T...>>;
template <size_t idx, typename... T>
typename enable_if<TS<T...>::value == idx + 1, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return o << ", " << get<idx>(t) << ')';
}
template <size_t idx, typename... T>
typename enable_if<0 < idx && idx + 1 < TS<T...>::value, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return operator<< <idx + 1>(o << ", " << get<idx>(t), t);
}
template <size_t idx = 0, typename... T>
typename enable_if<1 < TS<T...>::value && !idx, ostream &>::type
operator<<(ostream &o, const tuple<T...> &t) {
  return operator<< <idx + 1>(o << '(' << get<idx>(t), t);
}
template <typename T> ostream &operator<<(ostream &o, const tuple<T> &t) {
  return o << get<0>(t);
}
template <typename T1, typename T2>
ostream &operator<<(ostream &o, const pair<T1, T2> &p) {
  return o << mt(p.fi, p.se);
}
template <typename C>
typename enable_if<IsC<C>::value, ostream &>::type operator<<(ostream &o,
                                                              const C &c) {
  o << '[';
  for (auto it = c.cbegin(); it != c.cend(); ++it)
    o << *it << (next(it) != c.cend() ? ", " : "");
  return o << ']';
}
template <typename T>
void tprint(vector<vector<T>> &v, size_t width = 0, ostream &o = cerr) {
  if (!DEBUG)
    return;
  for (auto &vv : v) {
    for (auto &i : vv)
      o << setw(width) << i;
    o << endl;
  }
}

void solve() {
  int n, m;
  ll k;
  cin >> n >> m >> k;
  vector<ll> as(n), bs(m);
  F0R(i, n) {
    cin >> as[i];
    if (i)
      as[i] += as[i - 1];
  }
  F0R(i, m) {
    cin >> bs[i];
    if (i)
      bs[i] += bs[i - 1];
  }
  dout << dvar(as) << dvar(bs) << endl;
  int best = 0;
  F0R(i, n) {
    if (as[i] > k)
      break;
    int bi = distance(bs.begin(), upper_bound(ALL(bs), k - as[i]));
    dout << dvar(i, bi) << endl;
    ckmax(best, i + 1 + bi);
  }
  F0R(i, m) {
    if (bs[i] > k)
      break;
    int ai = distance(as.begin(), upper_bound(ALL(as), k - bs[i]));
    dout << dvar(i, ai) << endl;
    ckmax(best, i + 1 + ai);
  }
  cout << best << endl;
}

int main() {
  ios_base::sync_with_stdio(0);
  cout.tie(0);

  int tt = 1;
  FOR(t, 1, tt + 1) {
    // cout << "Case #" << t << ": ";
    solve();
  }

  return 0;
}