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#include <iostream>
#include <fstream>
#include <array>
#include <vector>
#include <unordered_map>
#include <functional>
#include "util.h"
using Name = std::string;
using Part = std::array<int,4>;
using Cond = std::function<bool(const Part&)>;
using Rule = std::pair<Cond,Name>;
using Workflow = std::vector<Rule>;
using Workflows = std::unordered_map<Name,Workflow>;
const std::unordered_map<char,int> fields{ {'x', 0}, {'m', 1}, {'a', 2}, {'s', 3} };
std::pair<std::vector<Part>,Workflows> parse(const char* file)
{
using namespace util::separators;
Workflows wfs;
std::vector<Part> parts;
if (std::ifstream input{ file }; input.is_open())
{
std::string line;
std::getline(input,line);
while (not line.empty())
{
auto bw = line.find('{');
Name name = line.substr(0, bw);
std::vector<Rule> rules;
line = line.substr(bw + 1, line.size() - bw - 2);
for (auto srule : util::split<COMMA>(std::string_view{ line }))
{
auto tokens = util::split<COLON>(srule);
if (tokens.size() > 1)
{
int f = fields.at(tokens[0][0]);
int v = std::stoi(std::string(tokens[0].substr(2)));
switch (tokens[0][1])
{
case '<':
rules.push_back({
[f,v](const Part& p) { return p[f] < v; },
Name{ tokens[1] }
});
break;
default:
rules.push_back({
[f,v](const Part& p) { return p[f] > v; },
Name{ tokens[1] }
});
};
}
else
{
rules.push_back({
[](const Part& p) { return true; },
Name{ tokens[0] }
});
}
}
wfs.insert({ name, std::move(rules) });
std::getline(input,line);
}
while (not std::getline(input,line).eof())
{
Part part; int i{};
util::accumulate<COMMA>(std::string_view{ line }.substr(1, line.size() - 2),
[&part,&i](std::string_view& v)
{
part[i++] = std::stoi(std::string{ v.substr(2) });
}
);
parts.push_back(std::move(part));
}
}
return { std::move(parts), std::move(wfs) };
}
Name apply_workflow(const Workflow& wf, const Part& p)
{
for (const auto& rule : wf)
{
auto [cond, name] = rule;
if (cond(p)) return name;
}
return "R";
}
int value(const Part& p)
{
return p[0] + p[1] + p[2] + p[3];
}
int process(const Part& p, const Workflows& wfs)
{
Name wname = "in";
while (wname != "A")
{
if (wname == "R") return 0;
wname = apply_workflow(wfs.at(wname), p);
}
return value(p);
}
int main(int argc, char* argv[])
{
int answer{};
auto [parts, workflows] = parse(argv[1]);
for (const auto& part : parts)
{
answer += process(part, workflows);
}
std::cout << answer << std::endl;
return 0;
}
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