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#include <iostream>
#include <fstream>
#include <sstream>
#include <tuple>
#include <vector>
#include "util.h"
using Seeds = std::vector<long>;
using Step = std::vector<std::tuple<long,long,long>>;
using Almanac = std::vector<Step>;
constexpr char SEEDS[] = "seeds:";
std::pair<Seeds,Almanac> parse_input()
{
Seeds seeds;
Almanac almanac;
std::ifstream input{ "resources/input.txt" };
if (input.is_open())
{
std::string line;
/* Seeds */
long seed;
std::getline(input,line);
std::istringstream sline{ line };
sline >> util::skip<SEEDS>;
while (sline >> seed)
{
seeds.push_back(seed);
}
/* Mappings */
Step step;
long from, to, size;
while (not std::getline(input,line).eof())
{
if (line.empty()) continue;
if (std::isdigit(line[0]))
{
std::istringstream sline{ line };
sline >> to >> from >> size;
step.push_back(std::make_tuple(from, from + size, to - from));
}
else if (not step.empty())
{
almanac.push_back(std::move(step));
step = {};
}
}
almanac.push_back(std::move(step));
}
input.close();
return std::make_pair(std::move(seeds), std::move(almanac));
}
int main(void)
{
Seeds seeds;
Almanac almanac;
std::tie(seeds, almanac) = parse_input();
for (const auto& step : almanac)
{
for (auto& seed : seeds)
{
for (const auto& map : step)
{
if (std::get<0>(map) <= seed and seed < std::get<1>(map))
{
seed += std::get<2>(map);
break; // mappings in a step don't overlap
}
}
}
}
std::cout << *std::min_element(seeds.begin(), seeds.end()) << std::endl;
return 0;
}
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