백준 2292번: 벌집

문제 출처: https://www.acmicpc.net/problem/2292

규칙찾기.

1) 1

2) 2-7  

3) 8-19:   7+1 ~  7+6*2

4) 20-37: 19+1 ~ 19+6*3

5) 38-61: 38+1 ~ 37+6*4

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(reader.readLine());
    
        if(N == 1){
            System.out.println("1");
            return;
        }
        
        int start = 2, end = 7, depth = 1;
        
        while(true){
            if(start <= N && N <= end){
                System.out.println(depth+1);
                break;
            }
            else {
                ++depth;
                start = end+1;
                end += 6*depth;
            }
        }
    }
}