Tifa's CP Library

:heavy_check_mark: src/test_cpverifier/library-checker/kth_root_integer.test.cpp

Depends on

Code

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

#include "../../code/math/ikth_root.hpp"

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  i64 t;
  std::cin >> t;
  while (t--) {
    u64 x, k;
    std::cin >> x >> k;
    std::cout << tifa_libs::math::ikth_root(x, k) << '\n';
  }
  return 0;
}
#line 1 "src/test_cpverifier/library-checker/kth_root_integer.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/kth_root_integer"

#line 1 "src/code/math/ikth_root.hpp"



#line 1 "src/code/util/util.hpp"



#include <bits/stdc++.h>

template <class T>
constexpr T abs(T x) { return x < 0 ? -x : x; }

using i8 = int8_t;
using i16 = int16_t;
using i32 = int32_t;
using i64 = int64_t;
using i128 = __int128_t;
using isz = ptrdiff_t;

using u8 = uint8_t;
using u16 = uint16_t;
using u32 = uint32_t;
using u64 = uint64_t;
using u128 = __uint128_t;
using usz = size_t;

using f32 = float;
using f64 = double;
using f128 = long double;

template <class T>
using ptt = std::pair<T, T>;
template <class T>
using pt3 = std::tuple<T, T, T>;
template <class T>
using pt4 = std::tuple<T, T, T, T>;

template <class T, usz N>
using arr = std::array<T, N>;
template <class T>
using vec = std::vector<T>;
template <class T>
using vvec = vec<vec<T>>;
template <class T>
using v3ec = vec<vvec<T>>;
template <class U, class T>
using vecp = vec<std::pair<U, T>>;
template <class U, class T>
using vvecp = vvec<std::pair<U, T>>;
template <class T>
using vecpt = vec<ptt<T>>;
template <class T>
using vvecpt = vvec<ptt<T>>;

template <class T, class C = std::less<T>>
using pq = std::priority_queue<T, vec<T>, C>;
template <class T>
using pqg = std::priority_queue<T, vec<T>, std::greater<T>>;

using strn = std::string;
using strnv = std::string_view;

using vecu = vec<u32>;
using vvecu = vvec<u32>;
using v3ecu = v3ec<u32>;
using vecu64 = vec<u64>;
using vecb = vec<bool>;
using vvecb = vvec<bool>;

#ifdef ONLINE_JUDGE
#undef assert
#define assert(x) 42
#endif

using namespace std::literals;

constexpr i8 operator""_i8(unsigned long long x) { return (i8)x; }
constexpr i16 operator""_i16(unsigned long long x) { return (i16)x; }
constexpr i32 operator""_i32(unsigned long long x) { return (i32)x; }
constexpr i64 operator""_i64(unsigned long long x) { return (i64)x; }
constexpr isz operator""_iz(unsigned long long x) { return (isz)x; }

constexpr u8 operator""_u8(unsigned long long x) { return (u8)x; }
constexpr u16 operator""_u16(unsigned long long x) { return (u16)x; }
constexpr u32 operator""_u32(unsigned long long x) { return (u32)x; }
constexpr u64 operator""_u64(unsigned long long x) { return (u64)x; }
constexpr usz operator""_uz(unsigned long long x) { return (usz)x; }

inline const auto fn_0 = [](auto&&...) {};


#line 5 "src/code/math/ikth_root.hpp"

namespace tifa_libs::math {

constexpr u64 ikth_root(u64 a, u64 k) {
  assert(k);
  if (a <= 1 || k == 1) return a;
  if (k >= 64) return 1;
  auto chk = [&](u128 n) {
    u128 x = 1, m = n;
    for (u64 p = k; p; p /= 2, m *= m)
      if (p & 1) x *= m;
    return x <= a;
  };
  u64 n = (u64)powl(a, 1.l / k);
  while (!chk(n)) --n;
  while (chk(n + 1)) ++n;
  return n;
}

}  // namespace tifa_libs::math


#line 4 "src/test_cpverifier/library-checker/kth_root_integer.test.cpp"

int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  i64 t;
  std::cin >> t;
  while (t--) {
    u64 x, k;
    std::cin >> x >> k;
    std::cout << tifa_libs::math::ikth_root(x, k) << '\n';
  }
  return 0;
}

Test cases

Env Name Status Elapsed Memory
g++-12 all_k2_00 :heavy_check_mark: AC 330 ms 4 MB
g++-12 all_k2_01 :heavy_check_mark: AC 336 ms 4 MB
g++-12 all_k3_00 :heavy_check_mark: AC 316 ms 4 MB
g++-12 all_k3_01 :heavy_check_mark: AC 318 ms 4 MB
g++-12 all_k3_2_00 :heavy_check_mark: AC 340 ms 4 MB
g++-12 all_k3_2_01 :heavy_check_mark: AC 341 ms 4 MB
g++-12 example_00 :heavy_check_mark: AC 9 ms 4 MB
g++-12 near_border_00 :heavy_check_mark: AC 275 ms 4 MB
g++-12 near_border_01 :heavy_check_mark: AC 278 ms 4 MB
g++-12 near_border_02 :heavy_check_mark: AC 278 ms 4 MB
g++-12 near_border_2_00 :heavy_check_mark: AC 306 ms 4 MB
g++-12 near_border_2_01 :heavy_check_mark: AC 306 ms 4 MB
g++-12 near_border_2_02 :heavy_check_mark: AC 312 ms 4 MB
g++-12 random_00 :heavy_check_mark: AC 266 ms 4 MB
g++-12 random_01 :heavy_check_mark: AC 314 ms 4 MB
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