https://www.acmicpc.net/problem/1463

1로 만들기.java

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] num = new int[n+1];
        for (int i=2; i<=n; i++) {
            num[i] = num[i-1]+1;
            if (i%2==0 && num[i/2]+1 < num[i])
                num[i] = num[i/2]+1;
            if (i%3==0 && num[i/3]+1 < num[i])
                num[i] = num[i/3]+1;
        }
        System.out.print(num[n]);
    }
}