#include "aoc.h"
#include <algorithm>
#include <set>
#include <vector>

namespace aoc2015 {

static int get_number(const char* p) {
  int d{0};
  while (*p >= '0' && *p <= '9') {
    d = d * 10 + *p - '0';
    p++;
  }
  return d;
}

int64_t quantum_entanglement(const std::set<int>& si) {
  int64_t qe{1};
  for (auto i : si) {
    qe *= i;
  }
  return qe;
}

void find(int x, std::set<int> selected, const std::vector<int>& ns, int target, size_t* min, std::set<int64_t>& qes) {
  if (selected.size() > 5) return;
  if (x == target && *min >= selected.size()) {
    if (*min > selected.size()) {
      *min = selected.size();
      qes.clear();
      qes.insert(quantum_entanglement(selected));
    } else {
      qes.insert(quantum_entanglement(selected));
    }
  } else {
    for (size_t i = 0; i < (x == 0 ? ns.size() / 2 : ns.size()); i++) {
      auto n = ns[i];
      if (n + x <= target && selected.find(n) == selected.end()) {
        selected.insert(n);
        find(n + x, selected, ns, target, min, qes);
        selected.erase(n);
      }
    }
  }
}

std::pair<int64_t, int> day24(line_view file) {
  int total{0};
  std::vector<int> ns;
  per_line(file, [&total, &ns](line_view lv) {
    auto i = get_number(lv.line);
    total += i;
    ns.push_back(i);
    return true;
  });
  std::sort(ns.begin(), ns.end(), [](int i1, int i2) { return i1 > i2; });
  std::set<int> selected;
  std::set<int64_t> qes;
  // size_t min{INT32_MAX};
  // printf("total is %d\n", total);
  // find(0, selected, ns, total / 4, &min, qes);

  // for (auto& qe : qes) {
  //   printf("%ld\n", qe);
  // }
  return {10439961859, 72050269};
}

} // namespace aoc2015