3461 - Interferência em Luzes Hexagonais Lights

#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;

using i64 = long long;

const int TARGET = (1 << 10) - 1;
const int INF = 0x3f3f3f3f;

int a[10] = {
  (1 << 1) | (1 << 4), // 1
  (1 << 0) | (1 << 4) | (1 << 5) | (1 << 2), // 2
  (1 << 1) | (1 << 5) | (1 << 6) | (1 << 3), // 3
  (1 << 2) | (1 << 6), // 4
  (1 << 0) | (1 << 1) | (1 << 5) | (1 << 7), // 5
  (1 << 1) | (1 << 2) | (1 << 4) | (1 << 6) | (1 << 7) | (1 << 8), // 6
  (1 << 2) | (1 << 3) | (1 << 5) | (1 << 8), // 7
  (1 << 4) | (1 << 5) | (1 << 8) | (1 << 9), // 8
  (1 << 5) | (1 << 6) | (1 << 7) | (1 << 9), // 9
  (1 << 7) | (1 << 8) // 10
};

string get(int mask) {
  string s;

  for (int i = 0; i < 10; ++i) {
    s += ((mask & (1 << i)) ? "1" : "0");
  }

  return s;
}

bool cmp(string a, string b) {
  int sz = a.size();

  vector<int> aa, bb;

  for (int i = 0; i < sz; ++i) {
    if (a[i] == '1') {
      aa.push_back(i + 1);
    }
    if (b[i] == '1') {
      bb.push_back(i + 1);
    }
  }

  for (int i = 0; i < aa.size(); ++i) {
    if (aa[i] < bb[i]) return true;
    if (aa[i] > bb[i]) return false;
  }

  return false;
}

int main() {
  cin.tie(0)->sync_with_stdio(0);

  int initialMask = 0;
  for (int i = 0; i < 10; ++i) {
    int x; cin >> x;
    if (x)
      initialMask |= (1 << i);
  }

  int answer = INF;
  string strAns;
  for (int mask = 0; mask < (1 << 10); ++mask) {
    int allMasks = initialMask;

    for (int i = 0; i < 10; ++i) {
      if (mask & (1 << i)) {
        allMasks ^= a[i];
      }
    }

    if (allMasks == TARGET) {
      int qtd = __builtin_popcount(mask);
      if (qtd < answer or (qtd == answer and cmp(get(mask), strAns))) {
        answer = qtd;
        strAns = get(mask);
      }
    }
  }

  if (answer != INF) {
    cout << answer << '\n';
    bool first = true;
    vector<int> a;

    for (int i = 0; i < 10; ++i) {
      if (strAns[i] == '1') {
        a.push_back(i + 1);
      }
    }

    for (int i = 0; i < answer; ++i) {
      cout << a[i] << " \n"[i==answer-1];
    }
  } else {
    cout << "-1\n";
  }
}