random/hash_pair.hpp

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• Last update: 2026-08-30 21:41:42+09:00
• Include: #include "random/hash_pair.hpp"

Depends on

• random/base.hpp

Required by

• geo/closest_pair.hpp

Verified with

• test/2_library_checker/geometry/closest_pair.test.cpp
• test/2_library_checker/geometry/closest_pair_dc.test.cpp
• test/3_yukicoder/2167.test.cpp
• test/4_aoj/CGL_5_A.test.cpp

Code

#include "random/base.hpp"

template <typename T>
u64 hash_pair(pair<T, T> X) {
  static ll hash_base = 0;
  if (hash_base == 0) hash_base = RNG_64();
  return hash_base * X.fi + X.se;
}

#line 1 "random/base.hpp"

u64 RNG_64() {
  static u64 x_ = u64(chrono::duration_cast<chrono::nanoseconds>(
                      chrono::high_resolution_clock::now().time_since_epoch())
                          .count()) *
                  10150724397891781847ULL;
  x_ ^= x_ << 7;
  return x_ ^= x_ >> 9;
}

u64 RNG(u64 lim) {
  assert(lim > 0);
  return RNG_64() % lim;
}

ll RNG(ll l, ll r) {
  assert(l < r);
  return l + RNG_64() % (r - l);
}
#line 2 "random/hash_pair.hpp"

template <typename T>
u64 hash_pair(pair<T, T> X) {
  static ll hash_base = 0;
  if (hash_base == 0) hash_base = RNG_64();
  return hash_base * X.fi + X.se;
}

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