Files
advent-of-code/2015/puzzle-06-02.cc
2021-12-01 20:31:53 +00:00

116 lines
2.9 KiB
C++

#include <algorithm>
#include <cassert>
#include <iostream>
#include <regex>
#include <set>
#include <string>
enum class Action { TurnOn, Toggle, TurnOff };
using Point = std::pair<unsigned, unsigned>;
struct Command {
Command(std::string const &s) {
const char *re =
"(turn on|toggle|turn off)\\s(\\d+),(\\d+)\\sthrough\\s(\\d+),(\\d+)";
std::smatch m;
if (!std::regex_search(s, m, std::regex(re))) {
std::cerr << "Unable to interpret:" << s << "\n";
assert(false);
}
if (m.str(1) == std::string("turn on")) {
act_ = Action::TurnOn;
} else if (m.str(1) == std::string("turn off")) {
act_ = Action::TurnOff;
} else if (m.str(1) == std::string("toggle")) {
act_ = Action::Toggle;
} else {
assert(false);
}
bottom_left_.first = std::stoul(m.str(2), nullptr, 10);
bottom_left_.second = std::stoul(m.str(3), nullptr, 10);
top_right_.first = std::stoul(m.str(4), nullptr, 10);
top_right_.second = std::stoul(m.str(5), nullptr, 10);
}
Action act_;
Point bottom_left_;
Point top_right_;
};
template <unsigned N> struct Array {
Array() noexcept {
for (unsigned i = 0; i < N; ++i) {
for (unsigned j = 0; j < N; ++j) {
lights_[i][j] = 0;
}
}
}
void apply(Command const &command) noexcept {
assert(command.bottom_left_.first < N);
assert(command.bottom_left_.second < N);
assert(command.top_right_.first < N);
assert(command.top_right_.second < N);
for (unsigned i = command.bottom_left_.first; i <= command.top_right_.first;
++i) {
for (unsigned j = command.bottom_left_.second;
j <= command.top_right_.second; ++j) {
switch (command.act_) {
case Action::TurnOn:
++lights_[i][j];
break;
case Action::Toggle:
lights_[i][j] += 2;
break;
case Action::TurnOff:
if (lights_[i][j] > 0) {
--lights_[i][j];
}
break;
}
}
}
}
unsigned brightness() const noexcept {
unsigned count = 0;
for (unsigned i = 0; i < N; ++i) {
for (unsigned j = 0; j < N; ++j) {
count += lights_[i][j];
}
}
return count;
}
/// Output a bitmap
void bitmap() const {
unsigned max = 0;
for (unsigned i = 0; i < N; ++i) {
for (unsigned j = 0; j < N; ++j) {
if (lights_[i][j] > max) {
max = lights_[i][j];
}
}
}
std::cout << "P2\n" << N << " " << N << "\n" << max << "\n";
for (unsigned i = 0; i < N; ++i) {
for (unsigned j = 0; j < N; ++j) {
std::cout << lights_[i][j] << "\n";
}
}
}
unsigned lights_[N][N];
};
int main(int argc, char **argv) {
Array<1000> arr;
for (std::string line; std::getline(std::cin, line);) {
Command cmd(line);
arr.apply(cmd);
}
arr.bitmap();
std::cout << arr.brightness() << '\n';
return 0;
}