verify/number-theory/UNIT_enumerate_quotients.test.cpp

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Last update: 2026-08-11 23:01:09+09:00
Problem: https://judge.yosupo.jp/problem/aplusb

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Code

#define PROBLEM "https://judge.yosupo.jp/problem/aplusb"

#include "template/template.hpp"
#include "number-theory/enumerate-quotients.hpp"

using i64 = int64_t;

void check(i64 N) {
  vector<tuple<i64, i64, i64>> expected;
  for (i64 r = N; r > 0;) {
    i64 q = N / r;
    i64 l = N / (q + 1);
    expected.emplace_back(q, l, r);
    r = l;
  }

  vector<tuple<i64, i64, i64>> actual;
  EnumerateQuotients::iterate(N, [&](i64 q, i64 l, i64 r) { actual.emplace_back(q, l, r); });
  assert(actual == expected);

  for (auto [q, l, r] : expected) {
    assert((EnumerateQuotients::get_range(N, q) == pair<i64, i64>(l, r)));
  }
}

void check(i64 N, int k) {
  vector<tuple<i64, i64, i64>> expected;
  i64 r = Math::floor_root(N, k);
  while (r > 0) {
    i64 p = 1;
    rep(_, 0, k) p *= r;
    i64 q = N / p;
    i64 l = r - 1;
    while (l > 0) {
      p = 1;
      rep(_, 0, k) p *= l;
      if (N / p != q) break;
      l--;
    }
    expected.emplace_back(q, l, r);
    r = l;
  }

  vector<tuple<i64, i64, i64>> actual;
  EnumerateQuotients::iterate(N, k, [&](i64 q, i64 l, i64 r) { actual.emplace_back(q, l, r); });
  assert(actual == expected);

  vector<i64> qs;
  for (auto [q, l, r] : expected) {
    qs.push_back(q);
    assert((EnumerateQuotients::get_range(N, q, k) == pair<i64, i64>(l, r)));
  }
  assert(EnumerateQuotients::table(N, k) == qs);
}

int main() {
  rep(N, 1, 10001) check(N);
  check(1000000000000LL);
  check(1000000000001LL);
  assert((EnumerateQuotients::get_range(numeric_limits<i64>::max(), numeric_limits<i64>::max()) ==
          pair<i64, i64>(0, 1)));

  check(100, 1);
  rep(N, 1, 10001) rep(k, 2, 9) check(N, k);
  check(1000000000001LL, 2);
  check(numeric_limits<i64>::max(), 63);
  assert(EnumerateQuotients::table(42, numeric_limits<int>::max()) == vector<i64>({42}));
  assert((EnumerateQuotients::get_range(42, 42, numeric_limits<int>::max()) == pair<i64, i64>(0, 1)));

  int a, b;
  in(a, b);
  out(a + b);
}

#line 1 "verify/number-theory/UNIT_enumerate_quotients.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/aplusb"

#line 2 "template/template.hpp"
#include <bits/stdc++.h>
using namespace std;

#line 2 "template/macro.hpp"
#define rep(i, a, b) for (int i = (a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (int)(b) - 1; i >= (a); i--)
#define ALL(v) (v).begin(), (v).end()
#define UNIQUE(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define SZ(v) (int)v.size()
#define MIN(v) *min_element(ALL(v))
#define MAX(v) *max_element(ALL(v))
#define LB(v, x) int(lower_bound(ALL(v), (x)) - (v).begin())
#define UB(v, x) int(upper_bound(ALL(v), (x)) - (v).begin())
#define YN(b) cout << ((b) ? "YES" : "NO") << "\n";
#define Yn(b) cout << ((b) ? "Yes" : "No") << "\n";
#define yn(b) cout << ((b) ? "yes" : "no") << "\n";
#line 6 "template/template.hpp"

#line 2 "template/util.hpp"
using uint = unsigned int;
using ll = long long int;
using ull = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
template <class T>
using priority_queue_asc = priority_queue<T, vector<T>, greater<T>>;

template <class T, class S = T>
S SUM(const vector<T>& a) {
  return accumulate(ALL(a), S(0));
}
template <class T1, class T2>
inline bool chmin(T1& a, T2 b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2>
inline bool chmax(T1& a, T2 b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2>
inline bool chmin_opt(optional<T1>& a, T2 b) {
  if (!a || a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T1, class T2>
inline bool chmax_opt(optional<T1>& a, T2 b) {
  if (!a || a < b) {
    a = b;
    return true;
  }
  return false;
}

template <class T>
int popcnt(T x) {
  return __builtin_popcountll(x);
}
template <class T>
int topbit(T x) {
  return (x == 0 ? -1 : 63 - __builtin_clzll(x));
}
template <class T>
int lowbit(T x) {
  return (x == 0 ? -1 : __builtin_ctzll(x));
}
#line 8 "template/template.hpp"

#line 2 "template/inout.hpp"
struct Fast {
  Fast() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(15);
  }
} fast;

ostream& operator<<(ostream& os, __uint128_t x) {
  char buf[40];
  size_t k = 0;
  while (x > 0) buf[k++] = (char)(x % 10 + '0'), x /= 10;
  if (k == 0) buf[k++] = '0';
  while (k) os << buf[--k];
  return os;
}
ostream& operator<<(ostream& os, __int128_t x) {
  return x < 0 ? (os << '-' << (__uint128_t)(-x)) : (os << (__uint128_t)x);
}
template <class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N>& a);
template <class T1, class T2>
istream& operator>>(istream& is, pair<T1, T2>& p) {
  return is >> p.first >> p.second;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  return os << p.first << " " << p.second;
}
template <class T>
istream& operator>>(istream& is, vector<T>& a) {
  for (auto& v : a) is >> v;
  return is;
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& a) {
  for (auto it = a.begin(); it != a.end();) {
    os << *it;
    if (++it != a.end()) os << " ";
  }
  return os;
}
template <class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N>& a) {
  for (auto it = a.begin(); it != a.end();) {
    os << *it;
    if (++it != a.end()) os << " ";
  }
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const set<T>& st) {
  os << "{";
  for (auto it = st.begin(); it != st.end();) {
    os << *it;
    if (++it != st.end()) os << ",";
  }
  os << "}";
  return os;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const map<T1, T2>& mp) {
  os << "{";
  for (auto it = mp.begin(); it != mp.end();) {
    os << it->first << ":" << it->second;
    if (++it != mp.end()) os << ",";
  }
  os << "}";
  return os;
}

void in() {}
template <typename T, class... U>
void in(T& t, U&... u) {
  cin >> t;
  in(u...);
}
template <class... T>
void in_zip(int n, T&... t) {
  assert(n >= 0 && ((size(t) >= static_cast<size_t>(n)) && ...));
  for (int i = 0; i < n; i++) in(t[i]...);
}
void out() { cout << "\n"; }
template <typename T, class... U, char sep = ' '>
void out(const T& t, const U&... u) {
  cout << t;
  if (sizeof...(u)) cout << sep;
  out(u...);
}
template <class T, class U>
void out_opt(const optional<T>& opt, const U& fallback, ostream& os = cout) {
  if (opt.has_value())
    os << opt.value();
  else
    os << fallback;
  os << "\n";
}
template <class T, class U>
void out_opt(const vector<optional<T>>& vec, const U& fallback, ostream& os = cout) {
  for (auto it = vec.begin(); it != vec.end();) {
    if ((*it).has_value())
      os << (*it).value();
    else
      os << fallback;
    if (++it != vec.end()) os << " ";
  }
  os << "\n";
}

namespace IO {
template <class T, class... U>
T read(U&&... u) {
  T t = T(forward<U>(u)...);
  in(t);
  return t;
}
namespace Graph {
vector<vector<int>> unweighted(int n, int m, bool directed = false, int offset = 1) {
  vector<vector<int>> g(n);
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    u -= offset, v -= offset;
    g[u].push_back(v);
    if (!directed) g[v].push_back(u);
  }
  return g;
}
template <class T>
vector<vector<pair<int, T>>> weighted(int n, int m, bool directed = false, int offset = 1) {
  vector<vector<pair<int, T>>> g(n);
  for (int i = 0; i < m; i++) {
    int u, v;
    T w;
    cin >> u >> v >> w;
    u -= offset, v -= offset;
    g[u].push_back({v, w});
    if (!directed) g[v].push_back({u, w});
  }
  return g;
}
}  // namespace Graph
namespace Tree {
vector<vector<int>> unweighted(int n, bool directed = false, int offset = 1) {
  return Graph::unweighted(n, n - 1, directed, offset);
}
template <class T>
vector<vector<pair<int, T>>> weighted(int n, bool directed = false, int offset = 1) {
  return Graph::weighted<T>(n, n - 1, directed, offset);
}
vector<vector<int>> rooted(int n, bool to_root = true, bool to_leaf = true, int offset = 1) {
  vector<vector<int>> g(n);
  for (int i = 1; i < n; i++) {
    int p;
    cin >> p;
    p -= offset;
    if (to_root) g[i].push_back(p);
    if (to_leaf) g[p].push_back(i);
  }
  return g;
}
}  // namespace Tree
}  // namespace IO
#line 10 "template/template.hpp"

#line 2 "template/debug.hpp"
#ifdef LOCAL
#define debug 1
#define show(...) _show(0, #__VA_ARGS__, __VA_ARGS__)
#else
#define debug 0
#define show(...) true
#endif
template <class T>
void _show(int, T) {
  cerr << '\n';
}
template <class T1, class T2, class... T3>
void _show(int i, const T1& a, const T2& b, const T3&... c) {
  for (; a[i] != ',' && a[i] != '\0'; i++) cerr << a[i];
  cerr << ":" << b << " ";
  _show(i + 1, a, c...);
}
#line 2 "number-theory/enumerate-quotients.hpp"

#line 2 "math/util.hpp"

namespace Math {
template <class T>
T safe_mod(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  a %= b;
  return a >= 0 ? a : a + b;
}
template <class T>
T floor(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  return a >= 0 ? a / b : (a + 1) / b - 1;
}
template <class T>
T ceil(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  return a > 0 ? (a - 1) / b + 1 : a / b;
}
long long isqrt(long long n) {
  if (n <= 0) return 0;
  long long x = sqrt(n);
  while ((__int128)(x + 1) * (x + 1) <= n) x++;
  while ((__int128)x * x > n) x--;
  return x;
}
long long floor_root(long long n, int k) {
  assert(n >= 0);
  if (n == 0) return 0;
  assert(k >= 1);
  if (k == 1) return n;
  if (k > 64) return 1;
  long long x = round(pow((long double)n, 1.0L / k));
  auto check = [&](long long a) {
    if (a <= 0) return true;
    __int128_t p = 1;
    for (int i = 0; i < k; ++i)
      if ((p *= a) > n) return false;
    return true;
  };
  while (check(x + 1)) x++;
  while (!check(x)) x--;
  return x;
}
unsigned long long floor_root_unsigned(unsigned long long n, int k) {
  assert(k >= 1);
  if (n <= 1 || k == 1) return n;
  if (k >= 64) return 1;
  int bits = (64 + k - 1) / k;
  unsigned long long ok = 1, ng = min(n, 1ULL << bits);
  auto check = [&](unsigned long long a) {
    __uint128_t p = 1;
    for (int i = 0; i < k; i++) {
      p *= a;
      if (p > n) return false;
    }
    return true;
  };
  while (ok + 1 < ng) {
    unsigned long long mid = ok + (ng - ok) / 2;
    (check(mid) ? ok : ng) = mid;
  }
  return ok;
}
// return g=gcd(a,b)
// a*x+b*y=g
// - b!=0 -> 0<=x<|b|/g
// - b=0  -> ax=g
template <class T>
T ext_gcd(T a, T b, T& x, T& y) {
  T a0 = a, b0 = b;
  bool sgn_a = a < 0, sgn_b = b < 0;
  if (sgn_a) a = -a;
  if (sgn_b) b = -b;
  if (b == 0) {
    x = sgn_a ? -1 : 1;
    y = 0;
    return a;
  }
  T x00 = 1, x01 = 0, x10 = 0, x11 = 1;
  while (b != 0) {
    T q = a / b, r = a - b * q;
    x00 -= q * x01;
    x10 -= q * x11;
    swap(x00, x01);
    swap(x10, x11);
    a = b, b = r;
  }
  x = x00, y = x10;
  if (sgn_a) x = -x;
  if (sgn_b) y = -y;
  if (b0 != 0) {
    a0 /= a, b0 /= a;
    if (b0 < 0) a0 = -a0, b0 = -b0;
    T q = x >= 0 ? x / b0 : (x + 1) / b0 - 1;
    x -= b0 * q;
    y += a0 * q;
  }
  return a;
}
constexpr long long inv_mod(long long x, long long m) {
  x %= m;
  if (x < 0) x += m;
  long long a = m, b = x;
  long long y0 = 0, y1 = 1;
  while (b > 0) {
    long long q = a / b;
    swap(a -= q * b, b);
    swap(y0 -= q * y1, y1);
  }
  if (y0 < 0) y0 += m / a;
  return y0;
}
long long pow_mod(long long x, long long n, long long m) {
  if (m == 1) return 0;
  x = (x % m + m) % m;
  long long y = 1;
  while (n) {
    if (n & 1) y = y * x % m;
    x = x * x % m;
    n >>= 1;
  }
  return y;
}
constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
  if (m == 1) return 0;
  unsigned int _m = (unsigned int)(m);
  unsigned long long r = 1;
  unsigned long long y = x % m;
  if (y >= m) y += m;
  while (n) {
    if (n & 1) r = (r * y) % _m;
    y = (y * y) % _m;
    n >>= 1;
  }
  return r;
}
constexpr bool is_prime_constexpr(int n) {
  if (n <= 1) return false;
  if (n == 2 || n == 7 || n == 61) return true;
  if (n % 2 == 0) return false;
  long long d = n - 1;
  while (d % 2 == 0) d /= 2;
  constexpr long long bases[3] = {2, 7, 61};
  for (long long a : bases) {
    long long t = d;
    long long y = pow_mod_constexpr(a, t, n);
    while (t != n - 1 && y != 1 && y != n - 1) {
      y = y * y % n;
      t <<= 1;
    }
    if (y != n - 1 && t % 2 == 0) {
      return false;
    }
  }
  return true;
}
template <int n>
constexpr bool is_prime = is_prime_constexpr(n);
};  // namespace Math
#line 4 "number-theory/enumerate-quotients.hpp"

namespace EnumerateQuotients {
using i64 = int64_t;
i64 div(i64 a, i64 b) { return double(a) / b; };
vector<i64> table(i64 N) {
  i64 sq = Math::isqrt(N);
  vector<i64> xs(sq);
  iota(xs.begin(), xs.end(), 1);
  if (N <= 1e12) {
    for (i64 i = div(N, sq + 1); i > 0; i--) xs.push_back(div(N, i));
  } else {
    for (i64 i = N / (sq + 1); i > 0; i--) xs.push_back(N / i);
  }
  return xs;
}
pair<i64, i64> get_range(i64 N, i64 q) {
  i64 l = q == numeric_limits<i64>::max() ? 0 : (N <= 1e12 ? div(N, q + 1) : N / (q + 1));
  i64 r = N <= 1e12 ? div(N, q) : N / q;
  return {l, r};
}
template <class F>
void iterate(i64 N, F f) {
  i64 sq = Math::isqrt(N);
  if (N <= 1e12) {
    i64 x = N;
    for (i64 q = 1; x > sq; q++) {
      i64 y = div(N, q + 1);
      f(q, y, x);
      x = y;
    }
    for (; x > 0; x--) f(div(N, x), x - 1, x);
  } else {
    i64 x = N;
    for (i64 q = 1; x > sq; q++) {
      i64 y = N / (q + 1);
      f(q, y, x);
      x = y;
    }
    for (; x > 0; x--) f(N / x, x - 1, x);
  }
}

namespace internal {
i64 quotient_power(i64 N, i64 x, int k) {
  i64 p = 1;
  for (int e = 0; e < k; e++) {
    if (p > N / x) return 0;
    p *= x;
  }
  return N / p;
}
};  // namespace internal

pair<i64, i64> get_range(i64 N, i64 q, int k) {
  assert(N >= 0 && q >= 1 && k >= 1);
  if (k == 1) return get_range(N, q);
  i64 l = q == numeric_limits<i64>::max() ? 0 : Math::floor_root(N / (q + 1), k);
  i64 r = Math::floor_root(N / q, k);
  return {l, r};
}

template <class F>
void iterate(i64 N, int k, F f) {
  assert(N >= 0 && k >= 1);
  if (k == 1) {
    iterate(N, f);
    return;
  }
  if (N == 0) return;
  if (k >= 63) {
    f(N, 0, 1);
    return;
  }

  i64 s = Math::floor_root(N, k + 1);
  i64 max_q = internal::quotient_power(N, s + 1, k);
  i64 r = Math::floor_root(N, k);
  for (i64 q = 1; q <= max_q; q++) {
    i64 l = Math::floor_root(N / (q + 1), k);
    if (l < r) f(q, l, r);
    r = l;
  }
  for (; r > 0; r--) f(internal::quotient_power(N, r, k), r - 1, r);
}

vector<i64> table(i64 N, int k) {
  vector<i64> qs;
  iterate(N, k, [&](i64 q, i64, i64) { qs.push_back(q); });
  return qs;
}
};  // namespace EnumerateQuotients

/**
 * @brief 商の列挙
 * @docs docs/number-theory/enumerate-quotients.md
 */
#line 5 "verify/number-theory/UNIT_enumerate_quotients.test.cpp"

using i64 = int64_t;

void check(i64 N) {
  vector<tuple<i64, i64, i64>> expected;
  for (i64 r = N; r > 0;) {
    i64 q = N / r;
    i64 l = N / (q + 1);
    expected.emplace_back(q, l, r);
    r = l;
  }

  vector<tuple<i64, i64, i64>> actual;
  EnumerateQuotients::iterate(N, [&](i64 q, i64 l, i64 r) { actual.emplace_back(q, l, r); });
  assert(actual == expected);

  for (auto [q, l, r] : expected) {
    assert((EnumerateQuotients::get_range(N, q) == pair<i64, i64>(l, r)));
  }
}

void check(i64 N, int k) {
  vector<tuple<i64, i64, i64>> expected;
  i64 r = Math::floor_root(N, k);
  while (r > 0) {
    i64 p = 1;
    rep(_, 0, k) p *= r;
    i64 q = N / p;
    i64 l = r - 1;
    while (l > 0) {
      p = 1;
      rep(_, 0, k) p *= l;
      if (N / p != q) break;
      l--;
    }
    expected.emplace_back(q, l, r);
    r = l;
  }

  vector<tuple<i64, i64, i64>> actual;
  EnumerateQuotients::iterate(N, k, [&](i64 q, i64 l, i64 r) { actual.emplace_back(q, l, r); });
  assert(actual == expected);

  vector<i64> qs;
  for (auto [q, l, r] : expected) {
    qs.push_back(q);
    assert((EnumerateQuotients::get_range(N, q, k) == pair<i64, i64>(l, r)));
  }
  assert(EnumerateQuotients::table(N, k) == qs);
}

int main() {
  rep(N, 1, 10001) check(N);
  check(1000000000000LL);
  check(1000000000001LL);
  assert((EnumerateQuotients::get_range(numeric_limits<i64>::max(), numeric_limits<i64>::max()) ==
          pair<i64, i64>(0, 1)));

  check(100, 1);
  rep(N, 1, 10001) rep(k, 2, 9) check(N, k);
  check(1000000000001LL, 2);
  check(numeric_limits<i64>::max(), 63);
  assert(EnumerateQuotients::table(42, numeric_limits<int>::max()) == vector<i64>({42}));
  assert((EnumerateQuotients::get_range(42, 42, numeric_limits<int>::max()) == pair<i64, i64>(0, 1)));

  int a, b;
  in(a, b);
  out(a + b);
}