杭电多校 Shortest path 记忆化搜索

‍ Shortest path

输入

4
7
114514
1919810
2147483648

输出

3
19
20
31

---

思路：用操作3 凑出 操作1 操作2 的前提条件，暴搜+记忆化搜索

import java.io.*;
import java.util.*;

public class Main
{
	static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
	static BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));
	static HashMap<Long, Integer> map = new HashMap<>();

	public static void main(String[] args) throws IOException
	{

		int T = Integer.parseInt(in.readLine());
		while (T-- > 0)
		{
			long n = Long.parseLong(in.readLine());
			map.clear();
			int ans = cal(n);
			out.write(ans + "\n");
		}
		out.flush();
	}

	public static int cal(long n)
	{
		if (n <= 1)
			return (int) (1 - n);

		if (map.containsKey(n))
			return map.get(n);

		int t1 = (int) (n % 2 + 1 + cal(n / 2));
		int t2 = (int) (n % 3 + 1 + cal(n / 3));
		int ans = Math.min(t1, t2);
		map.put(n, ans);

		return ans;
	}

}

‍ 参考