105 lines
2.1 KiB
C++
105 lines
2.1 KiB
C++
#include <algorithm>
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#include <concepts>
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#include <cstdint>
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#include <iostream>
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#include <set>
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#include <sstream>
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#include <stdexcept>
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#include <string>
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#include <tuple>
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#include <utility>
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#include <vector>
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#include <doctest.h>
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#include <aocpp/Startup.hpp>
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#include <aocpp/Vec.hpp>
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namespace {
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using Coord = aocpp::Vec<std::int64_t, 3>;
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/// @brief Parse an input stream
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/// @param in white-space delimited, comma-separated coordinates
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/// @return set of coordinates
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auto Parse(std::istream & in) -> std::set<Coord>
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{
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std::set<Coord> result;
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std::string line;
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while (in >> line) {
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Coord x;
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if (3 != std::sscanf(line.c_str(), "%lld,%lld,%lld\n", &x[0], &x[1], &x[2]))
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throw std::runtime_error{"bad input line"};
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result.insert(x);
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}
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return result;
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}
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auto Part1(std::set<Coord> const& obj) -> std::size_t
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{
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std::size_t result {0};
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for (auto && x : obj) {
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x.EachNeighbor([&](Coord const& y) {
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if (!obj.contains(y)) result++;
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});
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}
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return result;
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}
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auto Part2(std::set<Coord> const& obj) -> std::size_t
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{
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auto [lo, hi] = Coord::BoundingBox(obj.begin(), obj.end());
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lo -= Coord(1);
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hi += Coord(1);
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std::set<Coord> seen {lo};
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std::vector<Coord> work {lo};
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std::size_t result {0};
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while (!work.empty()) {
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auto x = work.back();
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work.pop_back();
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x.EachNeighbor([&, lo=lo, hi=hi](Coord const& y) {
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if (obj.contains(y)) {
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result++;
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} else if (y.InRange(lo, hi) && seen.insert(y).second) {
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work.push_back(y);
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}
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});
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}
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return result;
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}
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} // namespace
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TEST_SUITE("2022-12 examples") {
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TEST_CASE("documented example") {
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std::istringstream in {
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"2,2,2\n"
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"1,2,2\n"
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"3,2,2\n"
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"2,1,2\n"
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"2,3,2\n"
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"2,2,1\n"
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"2,2,3\n"
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"2,2,4\n"
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"2,2,6\n"
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"1,2,5\n"
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"3,2,5\n"
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"2,1,5\n"
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"2,3,5\n"
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};
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auto obj = Parse(in);
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CHECK(64 == Part1(obj));
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CHECK(58 == Part2(obj));
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}
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}
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auto Main(std::istream & in, std::ostream & out) -> void
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{
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auto const obj {Parse(in)};
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out << "Part 1: " << Part1(obj) << std::endl;
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out << "Part 2: " << Part2(obj) << std::endl;
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}
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