cp-includes/Epsilon.cpp at master · rsalesc/cp-includes · GitHub

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#ifndef _LIB_EPSILON
#define _LIB_EPSILON
#include <bits/stdc++.h>

namespace lib {
using namespace std;

template <typename T = double> struct Epsilon {
  T eps;
  constexpr Epsilon(T eps = 1e-9) : eps(eps) {}

  template <typename G,
            typename enable_if<is_floating_point<G>::value>::type * = nullptr>
  int operator()(G a, G b = 0) const {
    return a + eps < b ? -1 : (b + eps < a ? 1 : 0);
  }

  template <typename G,
            typename enable_if<!is_floating_point<G>::value>::type * = nullptr>
  int operator()(G a, G b = 0) const {
    return a < b ? -1 : (a > b ? 1 : 0);
  }

  template <typename G,
            typename enable_if<is_floating_point<G>::value>::type * = nullptr>
  bool null(G a) const {
    return (*this)(a) == 0;
  }

  template <typename G,
            typename enable_if<!is_floating_point<G>::value>::type * = nullptr>
  bool null(G a) const {
    return a == 0;
  }
};
} // namespace lib

#endif