Counter

#include <iostream>
#include <cmath>
#include <vector>
#include <cassert>
#include <algorithm>
#include <queue>
using namespace std;
#define rep(i, a, b) for(int i=a;i<(b);++i)
#define all(x) begin(x),end(x)
#define sz(x) int((x).size())
using ll = long long;
using pii = pair<int,int>;
using vi = vector<int>;

const int N = 1e6+1;
bool R[N];

int main() {
  int x;
  cin >> x;
  priority_queue<pair<int,int>> q;
  q.push({0,0});
  R[0] = 1;
  while (!q.empty()) {
    auto [s,n] = q.top(); q.pop();
    if (n == x) {
      cout << s << '\n';
      return 0;
    }
    if (n-2 >= 0 && !R[n-2]) {
      R[n-2] = 1;
      q.push({s+1,n-2});
    }
    if (n+11 <= x && !R[n+11]) {
      R[n+11] = 1;
      q.push({s+1,n+11});
    }
  }
  cout << "-1\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED