试题 E: 回路计数 蓝桥杯 Java 2021省赛A组

package javaa2021;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;

public class pe3 {
	static int n = 21;
	static int huzhi = 1;
	static int buhuzhi = 0;
	static ArrayList<Integer> list[];
	static int[] yifanru = new int[n + 1];
	static HashMap<HashSet<Integer>, Long> maps[];
	public static void main(String[] args) {
		list = new ArrayList[n + 1];
		maps = new HashMap[n + 1];
		for (int i = 0; i <= n; i++) {
			list[i] = new ArrayList<>();
		}
		for (int i = 0; i <= n; i++) {
			maps[i] = new HashMap<>();
		}
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j < i; j++) {
				if(pd(i, j) == huzhi) {
					list[i].add(j);
					list[j].add(i);
				}
			}
		}
		HashSet<Integer> hashSet = new HashSet<>();
		long ans = dfs(1, 1, hashSet);
		System.out.println(ans);
	}
	
	public static long dfs(int ganjiaru, int jiarugeshu, HashSet<Integer> hashSet) {
		if (jiarugeshu == n) {
			return 1;
		}
		HashSet<Integer> tempHashSet = new HashSet<>();
		tempHashSet.addAll(hashSet);
		tempHashSet.add(ganjiaru);
		if (maps[ganjiaru].containsKey(tempHashSet)) {
			return maps[ganjiaru].get(tempHashSet);
		}
		yifanru[ganjiaru] = 1;
		hashSet.add(ganjiaru);
		long ans = 0;
		for(int i: list[ganjiaru]) {
			if (yifanru[i] == 0) {
				ans += dfs(i, jiarugeshu + 1, hashSet);
			}
		}
		hashSet.remove(ganjiaru);
		yifanru[ganjiaru] = 0;
		if (!maps[ganjiaru].containsKey(tempHashSet)) {
			maps[ganjiaru].put(tempHashSet, ans);
		}
		return ans;
	}
	
	public static int pd(int a, int b) {
		if (a == 1 || b == 1) {
			return huzhi;
		}
		int min = Math.max(a, b);
		for (int i = 2; i <= min; i++) {
			if (a % i == 0 && b % i == 0) {
				return buhuzhi;
			}
		}
		return huzhi;
	}
}

最后

以上就是长情哈密瓜为你收集整理的试题 E: 回路计数 蓝桥杯 Java 2021省赛A组的全部内容，希望文章能够帮你解决试题 E: 回路计数 蓝桥杯 Java 2021省赛A组所遇到的程序开发问题。

如果觉得靠谱客网站的内容还不错，欢迎将靠谱客网站推荐给程序员好友。