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#include "aoc.h"
namespace aoc2015 {
std::pair<int, int> day19(line_view file) {
molecule m;
per_line(file, [&m](line_view lv) {
m.parse(lv);
return true;
});
std::map<int, std::vector<molecule::change>> changes;
m.check(changes);
// int shortest = INT32_MAX;
// m.deduct(m.original, 0, &shortest);
// m.transfer("e", 0, &shortest);
int steps = 0;
line_view lv = m.original;
std::vector<molecule::pattern> ps;
do {
lv = m.replace(lv, &steps);
// printf("%d\n", steps);
ps.clear();
const char* x = nullptr;
m.parse_pattern(lv, 0, ps, &x);
// std::for_each(ps.begin(), ps.end(),
// [](molecule::pattern p) { std::cout << p.depth << " -> " << p.lv << std::endl; });
if (ps[0].lv == "e") {
break;
}
if (ps[0].lv.contains("Y")) {
std::vector<line_view> ys;
m.parse_y(ps[0].lv, ys);
for (auto y : ys) {
if (m.transfers.find(y) == m.transfers.end()) {
line_view to = m.deduce(y, &steps);
lv = m.replace(lv, {y, to}, y.line);
break;
}
}
} else {
line_view to = m.deduce(ps[0].lv, &steps);
if (!(to == ps[0].lv)) {
lv = m.replace(lv, {ps[0].lv, to}, ps[0].lv.line);
} else {
lv = m.deduce(lv, ps[0].lv.line - 2, &steps);
}
}
} while (true);
return {m.distinct(changes), steps};
}
} // namespace aoc2015
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