Problem p03652 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;

// tourist set
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() { cerr << '\n'; }

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

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

#define FOR(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep(i, b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout << (s) << '\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define p_yes() p("YES")
#define p_no() p("NO")
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())

void no() {
  p_no();
  exit(0);
}
void yes() {
  p_yes();
  exit(0);
}

const ll mod = 1e9 + 7;
const ll inf = 1e18;

pair<ll, ll> f(map<ll, ll> &mp) {
  ll ans = 0;
  ll max_sport_id = -1;
  for (auto pa : mp) {
    ll count = pa.second;
    if (count > ans) {
      ans = count;
      max_sport_id = pa.first;
    }
    chmax(ans, pa.second);
  }
  return make_pair(ans, max_sport_id);
}

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

  // input
  ll N, M;
  cin >> N >> M;

  vector<VI> A;
  rep(i, N) {
    VI B;
    rep(j, M) {
      ll a;
      cin >> a;
      a--;
      B.push_back(a);
    }
    A.push_back(B);
  }

  // 先頭を見る
  map<ll, ll> mp;
  rep(i, N) {
    ll head = A[i][0];
    mp[head]++;
  }

  auto temp = f(mp);
  ll ans = temp.first;
  ll max_sport_id = temp.second;
  debug(ans, max_sport_id);

  vector<bool> deleted(N);

  ll LOOP = M - 1;
  mp.clear();
  while (LOOP--) {
    deleted[max_sport_id] = true;

    mp.clear();
    rep(i, N) {
      rep(j, M) {
        ll sport_id = A[i][j];
        if (!deleted[sport_id]) {
          // それを選択
          mp[sport_id]++;
          break;
        }
      }
    }

    // 今回の一番多く出たIDは？
    auto pa = f(mp);
    ll count = pa.first;
    ll id = pa.second;
    chmin(ans, count);
    max_sport_id = id;
  }

  //

  p(ans);

  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;

// tourist set
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() { cerr << '\n'; }

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

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

#define FOR(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep(i, b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout << (s) << '\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define p_yes() p("YES")
#define p_no() p("NO")
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())

void no() {
  p_no();
  exit(0);
}
void yes() {
  p_yes();
  exit(0);
}

const ll mod = 1e9 + 7;
const ll inf = 1e18;

pair<ll, ll> f(map<ll, ll> &mp) {
  ll ans = 0;
  ll max_sport_id = -1;
  for (auto pa : mp) {
    ll count = pa.second;
    if (count > ans) {
      ans = count;
      max_sport_id = pa.first;
    }
    chmax(ans, pa.second);
  }
  return make_pair(ans, max_sport_id);
}

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

  // input
  ll N, M;
  cin >> N >> M;

  vector<VI> A;
  rep(i, N) {
    VI B;
    rep(j, M) {
      ll a;
      cin >> a;
      a--;
      B.push_back(a);
    }
    A.push_back(B);
  }

  // 先頭を見る
  map<ll, ll> mp;
  rep(i, N) {
    ll head = A[i][0];
    mp[head]++;
  }

  auto temp = f(mp);
  ll ans = temp.first;
  ll max_sport_id = temp.second;
  debug(ans, max_sport_id);

  vector<bool> deleted(M);

  ll LOOP = M - 1;
  mp.clear();
  while (LOOP--) {
    deleted[max_sport_id] = true;

    mp.clear();
    rep(i, N) {
      rep(j, M) {
        ll sport_id = A[i][j];
        if (!deleted[sport_id]) {
          // それを選択
          mp[sport_id]++;
          break;
        }
      }
    }

    // 今回の一番多く出たIDは？
    auto pa = f(mp);
    ll count = pa.first;
    ll id = pa.second;
    chmin(ans, count);
    max_sport_id = id;
  }

  //

  p(ans);

  return 0;
}