Problem p03558 (C++)

Buggy submission (status: Time Limit Exceeded):
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rep1(i, n) for (int i = 1; i < (int)(n); ++i)
#define repeq(i, n) for (int i = 0; i <= (int)(n); ++i)
#define rep1eq(i, n) for (int i = 1; i <= (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define rrep1(i, n) for (int i = (int)(n)-1; i > 0; --i)
#define rrepeq(i, n) for (int i = (int)(n); i >= 0; --i)
#define rrep1eq(i, n) for (int i = (int)(n); i > 0; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vb = vector<bool>;
template <typename T> using Graph = vector<vector<T>>;
template <typename T> using Spacial = vector<vector<vector<T>>>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int MOD = 1e9 + 7;
const int MOD2 = 998244353;
const double EPS = 1e-9;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

template <typename T> struct is_pair : false_type {};
template <typename T1, typename T2> struct is_pair<pair<T1, T2>> : true_type {};
template <typename T> struct is_vector : false_type {};
template <typename T> struct is_vector<vector<T>> : true_type {};

template <typename T1, typename T2>
istream &operator>>(istream &istr, pair<T1, T2> &p) {
  istr >> p.first >> p.second;
  return istr;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &ostr, const pair<T1, T2> &p) {
  ostr << p.first << " " << p.second;
  return ostr;
}
template <typename T> istream &operator>>(istream &istr, vector<T> &vec) {
  for (auto itr = vec.begin(); itr != vec.end(); ++itr) {
    istr >> *itr;
  }
  return istr;
}
template <typename T> ostream &operator<<(ostream &ostr, const vector<T> &vec) {
  if (vec.empty())
    return ostr;
  bool vp = is_vector<T>() || is_pair<T>();
  ostr << vec.front();
  for (auto itr = ++vec.begin(); itr != vec.end(); ++itr) {
    ostr << (vp ? "\n" : " ") << *itr;
  }
  return ostr;
}

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

int modpow(int a, long long n, int mod = MOD) {
  int ret = 1;
  do {
    if (n & 1)
      ret = 1LL * ret * a % mod;
    a = 1LL * a * a % mod;
  } while (n >>= 1);
  return ret;
}

template <typename T> T GCD(T a, T b) { return b ? GCD(b, a % b) : a; }
template <typename T> T LCM(T a, T b) { return a / GCD(a, b) * b; }

template <typename T1, typename T2>
bool CompareBySecond(pair<T1, T2> a, pair<T1, T2> b) {
  return a.second != b.second ? a.second < b.second : a.first < b.first;
}
template <typename T> bool CompareBySlope(pair<T, T> a, pair<T, T> b) {
  // counterclockwise from 12 o'clock direction
  if (a.first * b.first < 0)
    return a.first < b.first;
  if (a.first == 0)
    return a.second >= 0 || b.first > 0;
  if (b.first == 0)
    return b.second < 0 && a.first < 0;
  return a.second * b.first < a.first * b.second;
}

/* -------- <templates end> -------- */

void solve() {
  int k;
  cin >> k;

  while (k % 2 == 0)
    k /= 2;
  while (k % 5 == 0)
    k /= 5;

  if (k == 1) {
    cout << 1 << endl;
    return;
  }

  int n = 1;
  vi arr;

  do {
    n = n * 10 % k;
    arr.push_back(n);
  } while (n != 1);

  set<int> s;
  for (auto &v : arr)
    s.insert(v);

  queue<pair<int, vi>> q;
  q.push(make_pair(1, arr));

  int sz = arr.size();

  while (!q.empty()) {
    auto p = q.front();
    q.pop();
    rep(i, sz) {
      if (s.count(p.second[0] + arr[i]))
        continue;

      if (p.second[0] + arr[i] == k) {
        cout << p.first + 1 << endl;
        return;
      }

      vi sarr(sz);
      rep(j, sz) {
        sarr[j] = (p.second[j] + arr[(i + j) % sz]) % k;
        s.insert(sarr[j]);
      }
      q.push(make_pair(p.first + 1, sarr));
    }
  }
}

/* -------- <programs end> -------- */

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(12);
  solve();
  return 0;
}


Fixed submission:
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rep1(i, n) for (int i = 1; i < (int)(n); ++i)
#define repeq(i, n) for (int i = 0; i <= (int)(n); ++i)
#define rep1eq(i, n) for (int i = 1; i <= (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define rrep1(i, n) for (int i = (int)(n)-1; i > 0; --i)
#define rrepeq(i, n) for (int i = (int)(n); i >= 0; --i)
#define rrep1eq(i, n) for (int i = (int)(n); i > 0; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vb = vector<bool>;
template <typename T> using Graph = vector<vector<T>>;
template <typename T> using Spacial = vector<vector<vector<T>>>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int MOD = 1e9 + 7;
const int MOD2 = 998244353;
const double EPS = 1e-9;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

template <typename T> struct is_pair : false_type {};
template <typename T1, typename T2> struct is_pair<pair<T1, T2>> : true_type {};
template <typename T> struct is_vector : false_type {};
template <typename T> struct is_vector<vector<T>> : true_type {};

template <typename T1, typename T2>
istream &operator>>(istream &istr, pair<T1, T2> &p) {
  istr >> p.first >> p.second;
  return istr;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &ostr, const pair<T1, T2> &p) {
  ostr << p.first << " " << p.second;
  return ostr;
}
template <typename T> istream &operator>>(istream &istr, vector<T> &vec) {
  for (auto itr = vec.begin(); itr != vec.end(); ++itr) {
    istr >> *itr;
  }
  return istr;
}
template <typename T> ostream &operator<<(ostream &ostr, const vector<T> &vec) {
  if (vec.empty())
    return ostr;
  bool vp = is_vector<T>() || is_pair<T>();
  ostr << vec.front();
  for (auto itr = ++vec.begin(); itr != vec.end(); ++itr) {
    ostr << (vp ? "\n" : " ") << *itr;
  }
  return ostr;
}

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}

int modpow(int a, long long n, int mod = MOD) {
  int ret = 1;
  do {
    if (n & 1)
      ret = 1LL * ret * a % mod;
    a = 1LL * a * a % mod;
  } while (n >>= 1);
  return ret;
}

template <typename T> T GCD(T a, T b) { return b ? GCD(b, a % b) : a; }
template <typename T> T LCM(T a, T b) { return a / GCD(a, b) * b; }

template <typename T1, typename T2>
bool CompareBySecond(pair<T1, T2> a, pair<T1, T2> b) {
  return a.second != b.second ? a.second < b.second : a.first < b.first;
}
template <typename T> bool CompareBySlope(pair<T, T> a, pair<T, T> b) {
  // counterclockwise from 12 o'clock direction
  if (a.first * b.first < 0)
    return a.first < b.first;
  if (a.first == 0)
    return a.second >= 0 || b.first > 0;
  if (b.first == 0)
    return b.second < 0 && a.first < 0;
  return a.second * b.first < a.first * b.second;
}

/* -------- <templates end> -------- */

void solve() {
  int k;
  cin >> k;

  while (k % 2 == 0)
    k /= 2;
  while (k % 5 == 0)
    k /= 5;

  if (k == 1) {
    cout << 1 << endl;
    return;
  }

  int n = 1;
  vi arr;

  do {
    n = n * 10 % k;
    arr.push_back(n);
  } while (n != 1);

  set<int> s;
  for (auto &v : arr)
    s.insert(v);

  queue<pair<int, vi>> q;
  q.push(make_pair(1, arr));

  int sz = arr.size();

  while (!q.empty()) {
    auto p = q.front();
    q.pop();
    rep(i, sz) {
      if (s.count((p.second[0] + arr[i]) % k))
        continue;

      if (p.second[0] + arr[i] == k) {
        cout << p.first + 1 << endl;
        return;
      }

      vi sarr(sz);
      rep(j, sz) {
        sarr[j] = (p.second[j] + arr[(i + j) % sz]) % k;
        s.insert(sarr[j]);
      }
      q.push(make_pair(p.first + 1, sarr));
    }
  }
}

/* -------- <programs end> -------- */

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(12);
  solve();
  return 0;
}