106 lines
2.5 KiB
C++
106 lines
2.5 KiB
C++
#include <algorithm>
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#include <cstdint>
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#include <iostream>
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#include <numeric>
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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 <vector>
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#include <string_view>
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#include <boost/range/irange.hpp>
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#include <doctest.h>
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#include <aocpp/Startup.hpp>
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namespace {
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auto Parse(std::istream & in) -> std::vector<std::string>
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{
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std::vector<std::string> result;
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std::string line;
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while (std::getline(in, line)) {
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result.emplace_back(std::move(line));
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}
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return result;
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}
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auto Priority(char const c) -> std::int64_t
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{
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return c < 'a' ? c-'A'+27 : c-'a'+1;
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}
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auto Intersect(
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std::string::const_iterator start1, std::string::const_iterator end1,
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std::string::const_iterator start2, std::string::const_iterator end2
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) -> std::string
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{
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std::string common;
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std::set_intersection(
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start1, end1,
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start2, end2,
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std::back_inserter(common));
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return common;
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}
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auto Part1(std::vector<std::string> & input) -> std::int64_t
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{
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return std::transform_reduce(
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input.begin(), input.end(),
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std::int64_t{0}, std::plus(), // sum
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[](auto & line) {
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auto const mid = line.begin() + line.size() / 2;
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std::sort(line.begin(), mid);
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std::sort(mid, line.end());
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auto const common = Intersect(line.begin(), mid, mid, line.end());
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return Priority(common.at(0));
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});
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}
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auto Part2(std::vector<std::string> & input) -> std::int64_t
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{
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for (auto & line : input) {
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std::sort(line.begin(), line.end());
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}
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auto const range = boost::irange<std::size_t>(0, input.size(), 3);
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return std::transform_reduce(
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range.begin(), range.end(),
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std::int64_t{0}, std::plus(), // sum
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[&input](auto const i) {
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auto const input01 = Intersect(
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input[i ].begin(), input[i ].end(),
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input[i+1].begin(), input[i+1].end());
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auto const input012 = Intersect(
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input01 .begin(), input01 .end(),
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input[i+2].begin(), input[i+2].end());
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return Priority(input012.at(0));
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});
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}
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} // namespace
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TEST_SUITE("2022-03 examples") {
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TEST_CASE("example") {
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std::istringstream in {
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"vJrwpWtwJgWrhcsFMMfFFhFp\n"
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"jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL\n"
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"PmmdzqPrVvPwwTWBwg\n"
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"wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn\n"
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"ttgJtRGJQctTZtZT\n"
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"CrZsJsPPZsGzwwsLwLmpwMDw\n"};
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auto input = Parse(in);
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CHECK(Part1(input) == 157);
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CHECK(Part2(input) == 70);
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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 input {Parse(in)};
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out << "Part 1: " << Part1(input) << std::endl;
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out << "Part 2: " << Part2(input) << std::endl;
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}
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