141 lines
4.4 KiB
C++
141 lines
4.4 KiB
C++
|
#include <folly/String.h>
|
||
|
|
||
|
#include <fstream>
|
||
|
#include <iostream>
|
||
|
#include <map>
|
||
|
#include <numeric>
|
||
|
#include <regex>
|
||
|
#include <string>
|
||
|
#include <vector>
|
||
|
|
||
|
constexpr auto NEARBY_TICKETS_HEADER = "nearby tickets:";
|
||
|
constexpr auto YOUR_TICKET_HEADER = "your ticket:";
|
||
|
constexpr auto RANGE_PATTERN = R"((\d+)-(\d+) or (\d+)-(\d+))";
|
||
|
|
||
|
class TicketSpec {
|
||
|
public:
|
||
|
TicketSpec(
|
||
|
std::vector<int> &ourTicket, std::vector<std::vector<int>> &otherTickets,
|
||
|
std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> &fieldRanges)
|
||
|
: ourTicket(ourTicket), otherTickets(otherTickets), fieldRanges(fieldRanges) {
|
||
|
}
|
||
|
|
||
|
TicketSpec(
|
||
|
std::vector<int> &&ourTicket, std::vector<std::vector<int>> &&otherTickets,
|
||
|
std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> &&fieldRanges)
|
||
|
: ourTicket(std::move(ourTicket)), otherTickets(std::move(otherTickets)), fieldRanges(std::move(fieldRanges)) {
|
||
|
}
|
||
|
|
||
|
const std::vector<int> &getOurTicket() const {
|
||
|
return this->ourTicket;
|
||
|
}
|
||
|
|
||
|
const std::vector<std::vector<int>> &getOtherTickets() const {
|
||
|
return this->otherTickets;
|
||
|
}
|
||
|
|
||
|
const std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> &getFieldRanges() const {
|
||
|
return this->fieldRanges;
|
||
|
}
|
||
|
|
||
|
private:
|
||
|
std::vector<int> ourTicket;
|
||
|
std::vector<std::vector<int>> otherTickets;
|
||
|
// This has to be the grossest type signature I've written in a while, but it's of
|
||
|
// a-b or c-d maps to pair<a, b> or pair<c ,d>
|
||
|
std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> fieldRanges;
|
||
|
};
|
||
|
|
||
|
std::vector<std::string> readInput(const std::string &filename) {
|
||
|
std::vector<std::string> input;
|
||
|
std::string line;
|
||
|
std::ifstream file(filename);
|
||
|
while (std::getline(file, line)) {
|
||
|
input.push_back(line);
|
||
|
}
|
||
|
|
||
|
return input;
|
||
|
}
|
||
|
|
||
|
template <typename Iter>
|
||
|
std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> findPairs(Iter start, Iter end) {
|
||
|
std::vector<std::pair<std::pair<int, int>, std::pair<int, int>>> pairs;
|
||
|
std::regex rangeExpression(RANGE_PATTERN);
|
||
|
for (auto textIter = start; textIter != end; ++textIter) {
|
||
|
std::smatch matches;
|
||
|
if (!std::regex_search(*textIter, matches, rangeExpression)) {
|
||
|
throw new std::invalid_argument("Invalid input");
|
||
|
}
|
||
|
std::pair<int, int> range1(std::stoi(matches[1]), std::stoi(matches[2]));
|
||
|
std::pair<int, int> range2(std::stoi(matches[3]), std::stoi(matches[4]));
|
||
|
pairs.emplace_back(std::move(range1), std::move(range2));
|
||
|
}
|
||
|
|
||
|
return pairs;
|
||
|
}
|
||
|
|
||
|
std::vector<int> parseTicket(const std::string &rawTicket) {
|
||
|
std::vector<int> ticket;
|
||
|
folly::split(",", rawTicket, ticket);
|
||
|
|
||
|
return ticket;
|
||
|
}
|
||
|
|
||
|
template <typename Iter>
|
||
|
std::vector<std::vector<int>> parseNearbyTickets(Iter start, Iter end) {
|
||
|
std::vector<std::vector<int>> nearbyTickets;
|
||
|
for (auto it = start; it != end; ++it) {
|
||
|
auto ticket = parseTicket(*it);
|
||
|
nearbyTickets.push_back(std::move(ticket));
|
||
|
}
|
||
|
|
||
|
return nearbyTickets;
|
||
|
}
|
||
|
|
||
|
TicketSpec parseInput(const std::vector<std::string> &input) {
|
||
|
auto ruleEnd = std::find(input.cbegin(), input.cend(), "");
|
||
|
auto yourTicketBegin = std::find(input.cbegin(), input.cend(), YOUR_TICKET_HEADER);
|
||
|
auto nearbyTicketsBegin = std::find(input.cbegin(), input.cend(), NEARBY_TICKETS_HEADER);
|
||
|
auto pairs = findPairs(input.begin(), ruleEnd);
|
||
|
auto nearbyTickets = parseNearbyTickets(nearbyTicketsBegin + 1, input.cend());
|
||
|
auto yourTicket = parseTicket(*(yourTicketBegin + 1));
|
||
|
|
||
|
return TicketSpec(std::move(yourTicket), std::move(nearbyTickets), std::move(pairs));
|
||
|
}
|
||
|
|
||
|
bool inRangesForTicket(int value, const TicketSpec &ticketSpec) {
|
||
|
return std::any_of(
|
||
|
ticketSpec.getFieldRanges().cbegin(),
|
||
|
ticketSpec.getFieldRanges().cend(),
|
||
|
[value](const std::pair<std::pair<int, int>, std::pair<int, int>> &ranges) {
|
||
|
auto range1 = ranges.first;
|
||
|
auto range2 = ranges.second;
|
||
|
return (value >= range1.first && value <= range1.second) ||
|
||
|
(value >= range2.first && value <= range2.second);
|
||
|
});
|
||
|
}
|
||
|
|
||
|
int part1(const TicketSpec &ticketSpec) {
|
||
|
return std::accumulate(
|
||
|
ticketSpec.getOtherTickets().cbegin(),
|
||
|
ticketSpec.getOtherTickets().cend(),
|
||
|
0,
|
||
|
[&ticketSpec](int total, const std::vector<int> &ticket) {
|
||
|
return total + std::accumulate(ticket.cbegin(), ticket.cend(), 0, [&ticketSpec](int subtotal, int field) {
|
||
|
return inRangesForTicket(field, ticketSpec) ? subtotal : subtotal + field;
|
||
|
});
|
||
|
});
|
||
|
}
|
||
|
|
||
|
int main(int argc, char *argv[]) {
|
||
|
if (argc != 2) {
|
||
|
std::cerr << argv[0] << " <input_file>" << std::endl;
|
||
|
return 1;
|
||
|
}
|
||
|
|
||
|
auto input = readInput(argv[1]);
|
||
|
auto parsedInput = parseInput(input);
|
||
|
|
||
|
std::cout << part1(parsedInput) << std::endl;
|
||
|
}
|