Line data    Source code

       1              : #include "LinewiseInput.h"
       2              : #include "PuzzleImpl.h"
       3              : 
       4              : #include <libassert/assert.hpp>
       5              : #include <re2/re2.h>
       6              : 
       7              : #include <algorithm>
       8              : #include <cstdint>
       9              : #include <numeric>
      10              : 
      11              : namespace {
      12              : 
      13              : struct Present {
      14         2000 :   Present(std::string_view const s) {
      15         2000 :     static RE2 const boxPattern(R"((\d+)x(\d+)x(\d+))");
      16         2000 :     ASSUME(RE2::FullMatch(s, boxPattern, &l, &w, &h));
      17         2000 :   }
      18              : 
      19         1000 :   [[nodiscard]] uint64_t surfaceArea() const { return uint64_t(2) * (l * w + w * h + h * l); }
      20         1000 :   [[nodiscard]] uint64_t volume() const { return l * w * h; }
      21         1000 :   [[nodiscard]] uint64_t minFaceArea() const { return std::min({l * w, w * h, h * l}); }
      22         1000 :   [[nodiscard]] uint64_t minCircumference() const {
      23         1000 :     return uint64_t(2) * std::min({l + w, w + h, h + l});
      24         1000 :   }
      25              : 
      26         1000 :   [[nodiscard]] uint64_t requiredPaper() const { return surfaceArea() + minFaceArea(); }
      27         1000 :   [[nodiscard]] uint64_t requiredRibbon() const { return minCircumference() + volume(); }
      28              : 
      29              :   uint64_t l = 0u;
      30              :   uint64_t w = 0u;
      31              :   uint64_t h = 0u;
      32              : };
      33              : 
      34              : } // namespace
      35              : 
      36            1 : template <> size_t part1<2015, 2>(std::string_view const input) {
      37            1 :   LinewiseInput const lines(input);
      38            1 :   return std::transform_reduce(lines.begin(), lines.end(), uint64_t(0), std::plus<>{},
      39         1000 :                                [](std::string_view const s) { return Present(s).requiredPaper(); });
      40            1 : }
      41              : 
      42            1 : template <> size_t part2<2015, 2>(std::string_view const input) {
      43            1 :   LinewiseInput const lines(input);
      44            1 :   return std::transform_reduce(
      45            1 :       lines.begin(), lines.end(), uint64_t(0), std::plus<>{},
      46         1000 :       [](std::string_view const s) { return Present(s).requiredRibbon(); });
      47            1 : }