Codeforces 977D Divide by three, multiply by two(拓扑排序)
Polycarp likes to play with numbers. He takes some integer number xx, writes it down on the board, and then performs with it n−1n−1operations of the two kinds:
- divide the number xx by 33 (xx must be divisible by 33);
- multiply the number xx by 22.
After each operation, Polycarp writes down the result on the board and replaces xx by the result. So there will be nn numbers on the board after all.
You are given a sequence of length nn — the numbers that Polycarp wrote down. This sequence is given in arbitrary order, i.e. the order of the sequence can mismatch the order of the numbers written on the board.
Your problem is to rearrange (reorder) elements of this sequence in such a way that it can match possible Polycarp's game in the order of the numbers written on the board. I.e. each next number will be exactly two times of the previous number or exactly one third of previous number.
It is guaranteed that the answer exists.
The first line of the input contatins an integer number nn (2≤n≤1002≤n≤100) — the number of the elements in the sequence. The second line of the input contains nn integer numbers a1,a2,…,ana1,a2,…,an (1≤ai≤3⋅10181≤ai≤3⋅1018) — rearranged (reordered) sequence that Polycarp can wrote down on the board.
Print nn integer numbers — rearranged (reordered) input sequence that can be the sequence that Polycarp could write down on the board.
It is guaranteed that the answer exists.
6
4 8 6 3 12 9
9 3 6 12 4 8
4
42 28 84 126
126 42 84 28
2
1000000000000000000 3000000000000000000
3000000000000000000 1000000000000000000
In the first example the given sequence can be rearranged in the following way: [9,3,6,12,4,8][9,3,6,12,4,8]. It can match possible Polycarp's game which started with x=9x=9.
题目大意:给定的数组按照以下要求排序:后一个数是前一个数的三分之一,或者是前一个数的二倍。
思路:如果a[v]是a[u]的三分之一或者二倍,就给u->v加一条有向边,然后跑一遍拓扑排序就行了,注意得到的拓扑数组是下标
代码:
#include<cstdio>
#include<iostream>
#include<string>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<set>
#include<vector>
#include<map>
typedef long long ll;
using namespace std;
const int maxn = 200000 + 100;
int G[100 +10][100 + 10];
int c[maxn];
ll topo[maxn], t;
int n;
bool dfs(int u){
c[u] = -1;
for(int i = 0; i < n; i++)if(G[u][i]){
if(c[i] < 0)return false;
else if(!c[i] && !dfs(i))return false;
}
c[u] = 1;topo[--t] = u;
return true;
}
bool toposort(){
t = n;
memset(c, 0, sizeof(c));
for(int i = 0; i < n; i++)if(!c[i]){
if(!dfs(i)) return false;
}
return true;
}
int main(){
scanf("%d", &n);
ll a[maxn];
memset(G, 0, sizeof(G));
for(int i = 0; i < n; i++){
scanf("%lld", &a[i]);
}
sort(a, a+n);
for(int i = 0; i < n ; i++){
int it = lower_bound(a, a+n, a[i]/3)-a;
int itt = lower_bound(a, a+n, a[i]*2)-a;
if(a[i]%3==0&&a[it]==a[i]/3)G[i][it] = 1;
if(a[i]*2==a[itt])G[i][itt] = 1;
}
toposort();
for(int i = 0; i < n; i++)printf("%lld ", a[topo[i]]);
}
Codeforces 977D Divide by three, multiply by two(拓扑排序)的更多相关文章
- Codeforces Global Round 8 E. Ski Accidents(拓扑排序)
题目链接:https://codeforces.com/contest/1368/problem/E 题意 给出一个 $n$ 点 $m$ 边的有向图,每条边由编号较小的点通向编号较大的点,每个点的出度 ...
- codeforces 645 D. Robot Rapping Results Report 二分+拓扑排序
题目链接 我们可以发现, 这是一个很明显的二分+拓扑排序.... 如何判断根据当前的点, 是否能构造出来一个唯一的拓扑序列呢. 如果有的点没有出现, 那么一定不满足. 如果在加进队列的时候, 同时加了 ...
- codeforces 638B—— Making Genome in Berland——————【类似拓扑排序】
Making Genome in Berland time limit per test 1 second memory limit per test 256 megabytes input stan ...
- 【CodeForces 129 B】Students and Shoelaces(拓扑排序)
Anna and Maria are in charge of the math club for junior students. When the club gathers together, t ...
- Codeforces Round #460 (Div. 2)_D. Substring_[dp][拓扑排序]
题意:一个有向图,每个结点 被赋予一个小写字母,一条路径的value等与这条路径上出现次数最多的字母的数目,求该图的最大value 比赛时,用dfs超时,看官方题解用的dp和拓扑排序,a--z用0-2 ...
- Codeforces Round #479 (Div. 3) D. Divide by three, multiply by two
传送门 D. Divide by three, multiply by two •题意 给你一个数 x,有以下两种操作,x 可以任选其中一种操作得到数 y 1.如果x可以被3整除,y=x/3 2.y= ...
- codeforces 792C. Divide by Three
题目链接:codeforces 792C. Divide by Three 今天队友翻了个大神的代码来问,我又想了遍这题,感觉很好,这代码除了有点长,思路还是清晰易懂,我就加点注释存一下...分类吧. ...
- Codeforces Round #292 (Div. 1) B. Drazil and Tiles 拓扑排序
B. Drazil and Tiles 题目连接: http://codeforces.com/contest/516/problem/B Description Drazil created a f ...
- Codeforces Beta Round #29 (Div. 2, Codeforces format) C. Mail Stamps 离散化拓扑排序
C. Mail Stamps Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/problemset/problem ...
随机推荐
- FIND_IN_SET 精确查找
FIND_IN_SET(str,strlist) mysql专为精确匹配字符串而设置的函数 一个字符串列表就是一个由一些被‘,’符号分开的自链组成的字符串 1,2,3,4,5,6,7,8,9: 此函数 ...
- Javascript小白经典题型(一)
1. 输出是什么? function sayHi() { console.log(name) console.log(age) var name = 'Lydia' let age = 21 } sa ...
- Flink系列之Time和WaterMark
当数据进入Flink的时候,数据需要带入相应的时间,根据相应的时间进行处理. 让咱们想象一个场景,有一个队列,分别带着指定的时间,那么处理的时候,需要根据相应的时间进行处理,比如:统计最近五分钟的访问 ...
- 一步一步教你PowerBI利用爬虫获取天气数据分析
对于爬虫大家应该不会陌生,我们首先来看一下爬虫的定义:网络爬虫是一种自动获取网页内容的程序,是搜索引擎的重要组成部分.网络爬虫为搜索引擎从万维网下载网页,自动获取网页内容的应用程序.看到定义我们应该已 ...
- 详细解析Redis中的布隆过滤器及其应用
欢迎关注微信公众号:万猫学社,每周一分享Java技术干货. 什么是布隆过滤器 布隆过滤器(Bloom Filter)是由Howard Bloom在1970年提出的一种比较巧妙的概率型数据结构,它可以告 ...
- [Other]THUWC2020 游记
Dec. 20th 一下飞机,\(\text{FJ}\) 选手感觉 \(\text{BJ}\) 好冷 下午去了鸟巢,晚上回 \(\text{GLHT}\) 酒店吃泡面 写了洛谷上的线段树分治模板题之后 ...
- c语言-输出圆形
#include<stdio.h> #define high 100//定义界面大小 #define wide 100 void Circle(int ridus) //确定坐标 {int ...
- 从0开发3D引擎(八):准备“搭建引擎雏形”
大家好,现在开始本系列的第三部分,按照以下几个步骤来搭建引擎雏形: 1.分析引擎的需求 2.实现最小的3D程序 3.从中提炼引擎原型 4.一步一步地对引擎进行改进,使其具备良好的架构 5.实现与架构相 ...
- JSONArray 与 List 互转
List 转 JSONArray // 通过JSONPath获取其中数据,也可以说自己生成的List List<JSONObject> caseList = JsonPath.read(r ...
- 半夜了我来发张图 睡觉 ControllerDescriptor 与 ActionDescriptor 之间 的 关系