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  1. #include <iostream>
  2. #include <vector>
  3. #include <array>
  4. #include <iterator>
  5. using namespace std;
  6.  
  7. template<class T>
  8. struct slice {
  9.     T* data;
  10.     std::size_t const* stride;
  11.     slice operator[](std::size_t I)const {
  12.         return{ data + I* *stride, stride + 1 };
  13.     }
  14.     operator T&()const { return *data; }
  15.     T& operator=(T in) { *data = std::move(in); return *data; }
  16. };
  17.  
  18.  
  19. template<class T>
  20. struct buffer {
  21.     std::vector<T> data_;
  22.     std::vector<std::size_t> strides_;
  23.  
  24.     buffer(std::vector<std::size_t> sizes) :strides_(sizes) {
  25.         std::size_t scale = 1;
  26.         for (std::size_t i = 0; i < sizes.size(); ++i) {
  27.             auto next = strides_[sizes.size() - 1 - i] * scale;
  28.             strides_[sizes.size() - 1 - i] = scale;
  29.             scale = next;
  30.         }
  31.         data_.resize(scale);
  32.     }
  33.     const std::vector<std::size_t>& strides() const { return strides_; };
  34.     T* data() { return data_.data(); }
  35.     slice<T> get() { return{ data_.data(), strides_.data() }; }
  36.     slice<T> operator[](std::size_t I) { return get()[I]; }
  37.  
  38. };
  39.  
  40. int main() {
  41.     // your code goes here
  42.     buffer<int> b({ 2,5,3 });
  43.  
  44.     for (int i = 0; i < 2; i++)
  45.     {
  46.         for (int j = 0; j < 5; j++)
  47.         {
  48.             for (int k = 0; k < 3; k++)
  49.             {
  50.                 b[i][j][k] = 3 * (5 * (i)+j) + k + 1;
  51.             }
  52.         }
  53.     }
  54.     copy(b.data(), b.data() + 2 * 5 * 3, ostream_iterator<int>(cout, " "));
  55.     return 0;
  56. }
Success #stdin #stdout 0s 4356KB
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https://ideone.com/KH4OhE
multidimensional array https://stackoverflow.com/questions/47685777/fast-element-access-for-multi-dimensional-representation-of-contiguous-array
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
secret

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