ds/flat_ndvec.hpp

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• Last update: 2024-11-09 00:49:07+00:00
• Include: #include "ds/flat_ndvec.hpp"

Depends on

• prelude.hpp

Code

#pragma once
#include "prelude.hpp"

template <class T, int N>
class flat_ndvec {
 public:
  flat_ndvec(const int (&dim)[N], const T& elt = T())
      : data(accumulate(dim, dim + N, 1, multiplies()), elt) {
    for (int i = N, c = 1; i--;) factor[i] = c, c *= dim[i];
  }
  auto begin() { return data.begin(); }
  auto begin() const { return data.begin(); }
  auto end() { return data.end(); }
  auto end() const { return data.end(); }
  const T& operator[](const int (&is)[N]) const {
    int idx = 0;
    for (int i = 0; i < N; i++) idx += factor[i] * is[i];
    return data[idx];
  }
  T& operator[](const int (&is)[N]) {
    return const_cast<T&>(as_const(*this)[is]);
  }
  template <class... Ts>
  const T& operator()(Ts... is) const {
    return (*this)[{is...}];
  }
  template <class... Ts>
  T& operator()(Ts... is) {
    return (*this)[{is...}];
  }

 private:
  array<int, N> factor;
  vector<T> data;
};

#line 2 "prelude.hpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
using vc = vector<char>;
#define rep2(i, m, n) for (auto i = (m); i < (n); i++)
#define rep(i, n) rep2(i, 0, n)
#define repr2(i, m, n) for (auto i = (n); i-- > (m);)
#define repr(i, n) repr2(i, 0, n)
#define all(x) begin(x), end(x)
auto ndvec(int n, auto e) { return vector(n, e); }
auto ndvec(int n, auto ...e) { return vector(n, ndvec(e...)); }
auto comp_key(auto&& f) { return [&](auto&& a, auto&& b) { return f(a) < f(b); }; }
auto& max(const auto& a, const auto& b) { return a < b ? b : a; }
auto& min(const auto& a, const auto& b) { return b < a ? b : a; }
#if __cpp_lib_ranges
namespace R = std::ranges;
namespace V = std::views;
#endif
#line 3 "ds/flat_ndvec.hpp"

template <class T, int N>
class flat_ndvec {
 public:
  flat_ndvec(const int (&dim)[N], const T& elt = T())
      : data(accumulate(dim, dim + N, 1, multiplies()), elt) {
    for (int i = N, c = 1; i--;) factor[i] = c, c *= dim[i];
  }
  auto begin() { return data.begin(); }
  auto begin() const { return data.begin(); }
  auto end() { return data.end(); }
  auto end() const { return data.end(); }
  const T& operator[](const int (&is)[N]) const {
    int idx = 0;
    for (int i = 0; i < N; i++) idx += factor[i] * is[i];
    return data[idx];
  }
  T& operator[](const int (&is)[N]) {
    return const_cast<T&>(as_const(*this)[is]);
  }
  template <class... Ts>
  const T& operator()(Ts... is) const {
    return (*this)[{is...}];
  }
  template <class... Ts>
  T& operator()(Ts... is) {
    return (*this)[{is...}];
  }

 private:
  array<int, N> factor;
  vector<T> data;
};

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