2292 - 벌집

solution

code

#include <iostream>
#include <vector>
using namespace std;

int main()
{
    int N;
    cin >> N;
    vector<int> arr;
    arr.push_back(1);
    int elem = 1;
    int idx = 1;
    while(elem <= 1000000000)
    {
        elem += idx * 6;
        arr.push_back(elem);
        idx++;
    }
    int i = 0;
    while(N > arr[i]) i++;
    cout << i + 1 << endl;

    return 0;
}

ref

2292번: 벌집