Problem p02596 (C++) — buggy submission, verdict: Time Limit Exceeded


// Problem : C - Repsept
// Contest : AtCoder - AtCoder Beginner Contest 174
// URL : https://atcoder.jp/contests/abc174/tasks/abc174_c
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define endl '\\n'
#define maxl __LONG_LONG_MAX__
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define rep(i, n) for (int i = 0; i < n; i++)
#define rev(i, n) for (int i = n - 1; i >= 0; i--)
#define rep1(i, n) for (int i = 1; i < n; i++)
#define rev1(i, n) for (int i = n; i > 0; i--)
#define FOR(i, a, b) for (int i = a; i < b; i++)
#define trace(x) cerr << #x << ": " << x << endl;
#define trace2(x, y)                                                           \\
  cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z)                                                        \\
  cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": "   \\
       << z << endl;
#define trace4(a, b, c, d)                                                     \\
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \\
       << c << " | " << #d << ": " << d << endl;
#define cout1(a) cout << a << endl
#define cout2(a, b) cout << a << ' ' << b << endl
#define cout3(a, b, c) cout << a << " " << b << " " << c << endl
#define cout4(a, b, c, d) cout << a << " " << b << " " << c << " " << d << endl
#define coutvp(v, i) cout << v[i].fi << " " << v[i].se << endl
#define couta(a, n)                                                            \\
  for (ll i = 0; i < n; i++) {                                                 \\
    cout << a[i] << " ";                                                       \\
  }
#define n_ones(x) __builtin_popcountll(x)
#define n_trailzero(x) __builtin_ctzll(x)
#define n_leadingzero(x) __builtin_clz(x)
#define sz(a) (ll)(a.size())
#define all(v) v.begin(), v.end()
#define FASTIO                                                                 \\
  { ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL); }
#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) (a / gcd(a, b)) * b
#define PI 3.14159265358979323846
#define see(args...)                                                           \\
  {                                                                            \\
    cerr << "LINE " << __LINE__;                                               \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    err(_it, args);                                                            \\
    cerr << endl;                                                              \\
  }
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << ' ' << *it << " = " << a;
  err(++it, args...);
}
template <typename T, typename U> inline void min_self(T &x, U y) {
  if (y < x)
    x = y;
}
template <typename T, typename U> inline void max_self(T &x, U y) {
  if (x < y)
    x = y;
}
template <class T1, class T2>
ostream &operator<<(ostream &out, pair<T1, T2> pair) {
  return out << "(" << pair.first << ", " << pair.second << ")";
}
template <class T> ostream &operator<<(ostream &out, vector<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class T> ostream &operator<<(ostream &out, set<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class L, class R> ostream &operator<<(ostream &out, map<L, R> vec) {
  out << "(";
  for (auto &v : vec)
    out << "[" << v.first << ", " << v.second << "]";
  return out << ")";
}
template <class A, class B> istream &operator>>(istream &in, pair<A, B> &a) {
  return in >> a.first >> a.second;
}
template <class A> istream &operator>>(istream &in, vector<A> &a) {
  for (A &i : a)
    in >> i;
  return in;
}

typedef long long int ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pair<ll, ll>> vpll;
typedef vector<vector<ll>> vvll;
typedef stack<ll> stk;
typedef queue<ll> que;

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_setll;
typedef tree<char, null_type, less<char>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_setc;

ll max(int a, ll b) { return max((ll)a, b); }
ll min(int a, ll b) { return min((ll)a, b); }
ll min(ll a, int b) { return min(a, (ll)b); }
ll max(ll a, int b) { return max(a, (ll)b); }

// cout<<fixed<<setprecision(20)<<pi<<endl;

ll mod = 1e9 + 7;
ll Test, cas;

void solve() {
  ll k;
  cin >> k;
  if (k % 2 == 0)
    cout1(-1);
  else {
    ll ans = 0;
    ll rem = 7;
    ll mul = 7;
    while (ans <= 2e6) {
      if (rem % k == 0) {
        cout1((ans + 1));
        return;
      }
      mul *= 10;
      mul %= k;
      rem = (rem % k + (mul) % k) % k;
      ans++;
    }
    cout1(-1);
  }
  return;
}

int main() {
  FASTIO;
  Test = 1;
  // cin>>Test;
  for (cas = 1; cas <= Test; cas++)
    solve();
  return 0;
}


Error: TLE

Fixed submission:


// Problem : C - Repsept
// Contest : AtCoder - AtCoder Beginner Contest 174
// URL : https://atcoder.jp/contests/abc174/tasks/abc174_c
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define endl '\\n'
#define maxl __LONG_LONG_MAX__
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define rep(i, n) for (int i = 0; i < n; i++)
#define rev(i, n) for (int i = n - 1; i >= 0; i--)
#define rep1(i, n) for (int i = 1; i < n; i++)
#define rev1(i, n) for (int i = n; i > 0; i--)
#define FOR(i, a, b) for (int i = a; i < b; i++)
#define trace(x) cerr << #x << ": " << x << endl;
#define trace2(x, y)                                                           \\
  cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z)                                                        \\
  cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": "   \\
       << z << endl;
#define trace4(a, b, c, d)                                                     \\
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \\
       << c << " | " << #d << ": " << d << endl;
#define cout1(a) cout << a << endl
#define cout2(a, b) cout << a << ' ' << b << endl
#define cout3(a, b, c) cout << a << " " << b << " " << c << endl
#define cout4(a, b, c, d) cout << a << " " << b << " " << c << " " << d << endl
#define coutvp(v, i) cout << v[i].fi << " " << v[i].se << endl
#define couta(a, n)                                                            \\
  for (ll i = 0; i < n; i++) {                                                 \\
    cout << a[i] << " ";                                                       \\
  }
#define n_ones(x) __builtin_popcountll(x)
#define n_trailzero(x) __builtin_ctzll(x)
#define n_leadingzero(x) __builtin_clz(x)
#define sz(a) (ll)(a.size())
#define all(v) v.begin(), v.end()
#define FASTIO                                                                 \\
  { ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL); }
#define gcd(a, b) __gcd(a, b)
#define lcm(a, b) (a / gcd(a, b)) * b
#define PI 3.14159265358979323846
#define see(args...)                                                           \\
  {                                                                            \\
    cerr << "LINE " << __LINE__;                                               \\
    string _s = #args;                                                         \\
    replace(_s.begin(), _s.end(), ',', ' ');                                   \\
    stringstream _ss(_s);                                                      \\
    istream_iterator<string> _it(_ss);                                         \\
    err(_it, args);                                                            \\
    cerr << endl;                                                              \\
  }
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << ' ' << *it << " = " << a;
  err(++it, args...);
}
template <typename T, typename U> inline void min_self(T &x, U y) {
  if (y < x)
    x = y;
}
template <typename T, typename U> inline void max_self(T &x, U y) {
  if (x < y)
    x = y;
}
template <class T1, class T2>
ostream &operator<<(ostream &out, pair<T1, T2> pair) {
  return out << "(" << pair.first << ", " << pair.second << ")";
}
template <class T> ostream &operator<<(ostream &out, vector<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class T> ostream &operator<<(ostream &out, set<T> vec) {
  out << "(";
  for (auto &v : vec)
    out << v << ", ";
  return out << ")";
}
template <class L, class R> ostream &operator<<(ostream &out, map<L, R> vec) {
  out << "(";
  for (auto &v : vec)
    out << "[" << v.first << ", " << v.second << "]";
  return out << ")";
}
template <class A, class B> istream &operator>>(istream &in, pair<A, B> &a) {
  return in >> a.first >> a.second;
}
template <class A> istream &operator>>(istream &in, vector<A> &a) {
  for (A &i : a)
    in >> i;
  return in;
}

typedef long long int ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pair<ll, ll>> vpll;
typedef vector<vector<ll>> vvll;
typedef stack<ll> stk;
typedef queue<ll> que;

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_setll;
typedef tree<char, null_type, less<char>, rb_tree_tag,
             tree_order_statistics_node_update>
    indexed_setc;

ll max(int a, ll b) { return max((ll)a, b); }
ll min(int a, ll b) { return min((ll)a, b); }
ll min(ll a, int b) { return min(a, (ll)b); }
ll max(ll a, int b) { return max(a, (ll)b); }

// cout<<fixed<<setprecision(20)<<pi<<endl;

ll mod = 1e9 + 7;
ll Test, cas;

void solve() {
  ll k;
  cin >> k;
  if (k % 2 == 0)
    cout1(-1);
  else {
    ll ans = 0;
    ll rem = 7;
    ll mul = 7;
    while (1) {
      if (rem % k == 0) {
        cout1((ans + 1));
        return;
      }
      mul *= 10;
      mul %= k;
      rem = (rem % k + (mul) % k) % k;
      ans++;
    }
  }
  return;
}

int main() {
  FASTIO;
  Test = 1;
  // cin>>Test;
  for (cas = 1; cas <= Test; cas++)
    solve();
  return 0;
}