Problem p02574 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;

template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cout << endl; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cout << " " << to_string(H);
  debug_out(T...);
}

#define debug(...) cout << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)

const unsigned long long Mod = 1000000000 + 7;
typedef unsigned long long ull;

const ull maxA = 1000006;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ull n;
  cin >> n;
  vector<ull> v(n), cnt(maxA, 0);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    cnt[v[i]] += 1;
  }
  bool is_pair = true;
  for (int i = 2; i < maxA; i++) {
    int foo = 0;
    for (int j = i; j < maxA; j += i) {
      foo += cnt[j];
    }
    if (foo > 1) {
      is_pair = false;
      break;
    }
    if (!is_pair) {
      break;
    }
  }
  if (is_pair) {
    cout << "pairwise coprime";
    return 0;
  }
  auto gcd = [&](ull a, ull b) {
    while (b) {
      a %= b;
      swap(a, b);
    }
    return a;
  };

  ull g = v[0];
  for (int i = 1; i < n; i++) {
    g = gcd(g, v[i]);
  }
  if (g == 1) {
    cout << "setwise coprime";
  } else {
    cout << "not coprime";
  }
  return 0;
}


Error: WA

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

template <typename A, typename B> string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string &s) { return '"' + s + '"'; }

string to_string(const char *s) { return to_string((string)s); }

string to_string(bool b) { return (b ? "true" : "false"); }

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N> string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A> string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B> string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cout << endl; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cout << " " << to_string(H);
  debug_out(T...);
}

#define debug(...) cout << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)

const unsigned long long Mod = 1000000000 + 7;
typedef unsigned long long ull;

const ull maxA = 100005;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  ull n;
  cin >> n;
  vector<ull> v(n), cnt(maxA, 0);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    cnt[v[i]] += 1;
  }
  bool is_pair = true;
  for (int i = 2; i < maxA; i++) {
    int foo = 0;
    for (int j = i; j < maxA; j += i) {
      foo += cnt[j];
    }
    if (foo > 1) {
      is_pair = false;
      break;
    }
    if (!is_pair) {
      break;
    }
  }
  if (is_pair) {
    cout << "pairwise coprime";
    return 0;
  }
  auto gcd = [&](ull a, ull b) {
    while (b) {
      a %= b;
      swap(a, b);
    }
    return a;
  };

  ull g = v[0];
  for (int i = 1; i < n; i++) {
    g = gcd(g, v[i]);
  }
  if (g == 1) {
    cout << "setwise coprime";
  } else {
    cout << "not coprime";
  }
  return 0;
}