Problem p00884 (C++) — buggy submission, verdict: Runtime Error

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using namespace placeholders;

typedef long long LL;
typedef unsigned long long ULL;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef vector<string> VS;
typedef stringstream SS;
typedef pair<int, int> PII;
typedef vector<pair<int, int>> VPII;
#define VT(T) vector<T>
#define VVT(T) vector<vector<T>>
#define LIM(T) numeric_limits<T>

template <typename T> inline istream &operator>>(istream &s, vector<T> &v) {
  for (T &t : v) {
    s >> t;
  }
  return s;
}
template <typename T>
inline ostream &operator<<(ostream &s, const vector<T> &v) {
  for (int i = 0; i < int(v.size()); ++i) {
    s << (" " + !i) << v[i];
  }
  return s;
}
template <typename T> inline T fromString(const string &s) {
  T res;
  istringstream iss(s);
  iss >> res;
  return res;
};
template <typename T> inline string toString(const T &a) {
  ostringstream oss;
  oss << a;
  return oss.str();
};

#define REP2(i, n) REP3(i, 0, n)
#define REP3(i, m, n) for (int i = (int)(m); i < (int)(n); ++i)
#define GET_REP(a, b, c, F, ...) F
#define REP(...) GET_REP(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define FOR(e, c) for (auto &e : c)
#define ALL(c) (c).begin(), (c).end()
#define AALL(a, t) (t *)a, (t *)a + sizeof(a) / sizeof(t)
#define DRANGE(c, p) (c).begin(), (c).begin() + p, (c).end()

#define SZ(v) ((int)(v).size())
#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define EXIST(c, e) ((c).find(e) != (c).end())

#define MP make_pair
#define fst first
#define snd second

#define DUMP(x) cerr << #x << " = " << (x) << endl

// 文字列 split / デリミタに含まれるいずれかの文字で分割
vector<string> split(const string &str, const string &delim = " ") {
  int start = 0;
  vector<string> result;

  for (int pos; (pos = str.find_first_of(delim, start)) != (int)string::npos;
       start = pos + 1) {
    result.push_back(str.substr(start, pos - start));
  }
  result.push_back(str.substr(start));

  result.erase(
      remove_if(result.begin(), result.end(), not1(mem_fun_ref(&string::size))),
      result.end());

  return result;
}

map<string, VS> dp;
VS solve(const VS &groups, map<string, VS> &members, const string &group) {
  if (EXIST(dp, group)) {
    return dp[group];
  }

  VS res;
  FOR(member, members[group]) {
    if (EXIST(members, member)) {
      VS tmp = solve(groups, members, member);
      copy(ALL(tmp), BI(res));
    } else {
      res.PB(member);
    }
  }
  sort(ALL(res));
  res.erase(unique(ALL(res)), res.end());
  return dp[group] = res;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  for (int N; cin >> N && N;) {
    VS groups(N);
    map<string, VS> members;

    REP(i, N) {
      string s;
      cin >> s;

      const int colon = s.find(':');
      const string group = s.substr(0, colon);

      string ms = s.substr(colon + 1);
      ms.resize(SZ(ms) - 1);

      groups[i] = group;
      members[group] = split(ms, ",");
    }

    dp.clear();
    cout << SZ(solve(groups, members, groups[0])) << endl;
  }

  return 0;
}

Error: 0

Fixed submission:

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;
using namespace placeholders;

typedef long long LL;
typedef unsigned long long ULL;
typedef vector<int> VI;
typedef vector<vector<int>> VVI;
typedef vector<string> VS;
typedef stringstream SS;
typedef pair<int, int> PII;
typedef vector<pair<int, int>> VPII;
#define VT(T) vector<T>
#define VVT(T) vector<vector<T>>
#define LIM(T) numeric_limits<T>

template <typename T> inline istream &operator>>(istream &s, vector<T> &v) {
  for (T &t : v) {
    s >> t;
  }
  return s;
}
template <typename T>
inline ostream &operator<<(ostream &s, const vector<T> &v) {
  for (int i = 0; i < int(v.size()); ++i) {
    s << (" " + !i) << v[i];
  }
  return s;
}
template <typename T> inline T fromString(const string &s) {
  T res;
  istringstream iss(s);
  iss >> res;
  return res;
};
template <typename T> inline string toString(const T &a) {
  ostringstream oss;
  oss << a;
  return oss.str();
};

#define REP2(i, n) REP3(i, 0, n)
#define REP3(i, m, n) for (int i = (int)(m); i < (int)(n); ++i)
#define GET_REP(a, b, c, F, ...) F
#define REP(...) GET_REP(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define FOR(e, c) for (auto &e : c)
#define ALL(c) (c).begin(), (c).end()
#define AALL(a, t) (t *)a, (t *)a + sizeof(a) / sizeof(t)
#define DRANGE(c, p) (c).begin(), (c).begin() + p, (c).end()

#define SZ(v) ((int)(v).size())
#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define EXIST(c, e) ((c).find(e) != (c).end())

#define MP make_pair
#define fst first
#define snd second

#define DUMP(x) cerr << #x << " = " << (x) << endl

// 文字列 split / デリミタに含まれるいずれかの文字で分割
vector<string> split(const string &str, const string &delim = " ") {
  int start = 0;
  vector<string> result;

  for (int pos; (pos = str.find_first_of(delim, start)) != (int)string::npos;
       start = pos + 1) {
    result.push_back(str.substr(start, pos - start));
  }
  result.push_back(str.substr(start));

  result.erase(
      remove_if(result.begin(), result.end(), not1(mem_fun_ref(&string::size))),
      result.end());

  return result;
}

map<string, VS> dp;
VS solve(const VS &groups, map<string, VS> &members, const string &group) {
  if (EXIST(dp, group)) {
    return dp[group];
  }

  VS res;
  FOR(member, members[group]) {
    if (EXIST(members, member)) {
      VS tmp = solve(groups, members, member);
      copy(ALL(tmp), BI(res));
    } else {
      res.PB(member);
    }
  }
  return dp[group] = res;
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  for (int N; cin >> N && N;) {
    VS groups(N);
    map<string, VS> members;

    REP(i, N) {
      string s;
      cin >> s;

      const int colon = s.find(':');
      const string group = s.substr(0, colon);

      string ms = s.substr(colon + 1);
      ms.resize(SZ(ms) - 1);

      groups[i] = group;
      members[group] = split(ms, ",");
    }

    dp.clear();
    VS res = solve(groups, members, groups[0]);
    cout << SZ(set<string>(ALL(res))) << endl;
  }

  return 0;
}