Problem p02722 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template <class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i, a, n) for (int(i) = (a); (i) < (n); ++(i))
#define eFOR(i, a, n) for (int(i) = (a); (i) <= (n); ++(i))
#define rFOR(i, a, n) for (int(i) = (n)-1; (i) >= (a); --(i))
#define erFOR(i, a, n) for (int(i) = (n); (i) >= (a); --(i))
#define each(i, a) for (auto &i : a)
#define SORT(i) sort((i).begin(), (i).end())
#define rSORT(i, a) sort((i).begin(), (i).end(), (a))
#define all(i) (i).begin(), (i).end()
#define out(y, x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define line cout << "-----------------------------\\n"
#define ENDL(i, n) ((i) == (n)-1 ? "\\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
inline void init() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
}
template <class T> inline istream &operator>>(istream &is, vector<T> &v) {
  for (auto &elemnt : v)
    is >> elemnt;
  return is;
}
template <class T> inline istream &operator>>(istream &is, deque<T> &v) {
  for (auto &elemnt : v)
    is >> elemnt;
  return is;
}
template <class T, class U>
inline istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}
template <class T> inline vector<T> vec(size_t a) { return vector<T>(a); }
template <class T> inline vector<T> defvec(T def, size_t a) {
  return vector<T>(a, def);
}
template <class T, class... Ts> inline auto vec(size_t a, Ts... ts) {
  return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...));
}
template <class T, class... Ts> inline auto defvec(T def, size_t a, Ts... ts) {
  return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...));
}

ll _n;
map<ll, bool> ma;
bool solve(ll k) {
  if (k == 1)
    return false;
  ll n = _n;
  while (k <= n) {
    if (n % k == 0)
      n /= k;
    else
      n %= k;
  }
  return n == 1;
  if (n == 1 /* && (!ma.count(k))*/)
    cout << k << "\\n";
}

int main() {
  init();

  cin >> _n;
  int ans = 0;
  ma[_n], ma[_n - 1];
  for (ll i = 2; i * i <= _n - 1; ++i) {
    if ((_n - 1) % i == 0) {
      ++ans;
      if (i * i != _n - 1)
        ++ans;
    }
  }
  for (ll i = 2; i * i <= _n; ++i) {
    if (_n % i == 0) {
      ma[i];
      ma[_n / i];
    }
  }
  each(i, ma) if (solve(i.first))++ ans;
  cout << ans << "\\n";
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template <class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i, a, n) for (int(i) = (a); (i) < (n); ++(i))
#define eFOR(i, a, n) for (int(i) = (a); (i) <= (n); ++(i))
#define rFOR(i, a, n) for (int(i) = (n)-1; (i) >= (a); --(i))
#define erFOR(i, a, n) for (int(i) = (n); (i) >= (a); --(i))
#define each(i, a) for (auto &i : a)
#define SORT(i) sort((i).begin(), (i).end())
#define rSORT(i, a) sort((i).begin(), (i).end(), (a))
#define all(i) (i).begin(), (i).end()
#define out(y, x) ((y) < 0 || h <= (y) || (x) < 0 || w <= (x))
#define line cout << "-----------------------------\\n"
#define ENDL(i, n) ((i) == (n)-1 ? "\\n" : " ")
#define stop system("pause")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
inline void init() {
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
}
template <class T> inline istream &operator>>(istream &is, vector<T> &v) {
  for (auto &elemnt : v)
    is >> elemnt;
  return is;
}
template <class T> inline istream &operator>>(istream &is, deque<T> &v) {
  for (auto &elemnt : v)
    is >> elemnt;
  return is;
}
template <class T, class U>
inline istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}
template <class T> inline vector<T> vec(size_t a) { return vector<T>(a); }
template <class T> inline vector<T> defvec(T def, size_t a) {
  return vector<T>(a, def);
}
template <class T, class... Ts> inline auto vec(size_t a, Ts... ts) {
  return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...));
}
template <class T, class... Ts> inline auto defvec(T def, size_t a, Ts... ts) {
  return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...));
}

ll _n;
map<ll, bool> ma;
bool solve(ll k) {
  ll n = _n;
  while (k <= n) {
    if (n % k == 0)
      n /= k;
    else
      n %= k;
  }
  return n == 1;
  if (n == 1 /* && (!ma.count(k))*/)
    cout << k << "\\n";
}

int main() {
  init();

  cin >> _n;
  ma[_n], ma[_n - 1];
  for (ll i = 2; i * i <= _n - 1; ++i) {
    if ((_n - 1) % i == 0) {
      ma[i];
      ma[(_n - 1) / i];
    }
  }
  for (ll i = 2; i * i <= _n; ++i) {
    if (_n % i == 0) {
      ma[i];
      ma[_n / i];
    }
  }
  int ans = 0;
  each(i, ma) if (solve(i.first))++ ans;
  cout << ans << "\\n";
}