Kertoma

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;
using ll = long long;
ll t[20];

int main() {
  ll a = 0;
  for (int i = 0; i <= 9; ++i) {
    cin >> t[i];
    a += t[i];
  }
  //for (int i = 0; i <= 9; ++i) cout << i << " " << t[i] << endl;
  if (a == 1) {
    if (t[2]) cout << 2 << endl;
    else cout << 3 << endl;
  }
  else if (a == 3) {
    if (t[1]) cout << 5 << endl;
    else cout << 6 << endl;
  }
  else {
    ll ala = 2;
    ll yla = 1000000;
    ll c = -1;
    while (ala < yla) {
      ll keski = (ala+yla)/2;
      double b = keski * log10(keski / M_E) +log10(2 * M_PI * keski) / 2.0;
      //cout << ala << " " << yla << " " << floor(b)+1 << endl;
      if (floor(b)+1 == a) {
        c = keski;
        break;
      }
      else if (floor(b)+1 < a) ala = keski+1;
      else yla = keski-1;
    }
    if (c == -1) c = ala;
    cout << c << endl;
  }
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED

Test 16

Group: 3

Verdict: ACCEPTED