AtCoder Regular Contest 090 D - People on a Line
Problem Statement
There are N people standing on the x-axis. Let the coordinate of Person i be xi. For every i, xi is an integer between 0 and 109 (inclusive). It is possible that more than one person is standing at the same coordinate.
You will given M pieces of information regarding the positions of these people. The i-th piece of information has the form (Li,Ri,Di). This means that Person Ri is to the right of Person Li by Di units of distance, that is, xRi−xLi=Di holds.
It turns out that some of these M pieces of information may be incorrect. Determine if there exists a set of values (x1,x2,…,xN) that is consistent with the given pieces of information.
Constraints
- 1≤N≤100 000
- 0≤M≤200 000
- 1≤Li,Ri≤N (1≤i≤M)
- 0≤Di≤10 000 (1≤i≤M)
- Li≠Ri (1≤i≤M)
- If i≠j, then (Li,Ri)≠(Lj,Rj) and (Li,Ri)≠(Rj,Lj).
- Di are integers.
Input
Input is given from Standard Input in the following format:
N M
L1 R1 D1
L2 R2 D2
:
LM RM DM
Output
If there exists a set of values (x1,x2,…,xN) that is consistent with all given pieces of information, print Yes
; if it does not exist, print No
.
Sample Input 1
3 3
1 2 1
2 3 1
1 3 2
Sample Output 1
Yes
Some possible sets of values (x1,x2,x3) are (0,1,2) and (101,102,103).
Sample Input 2
3 3
1 2 1
2 3 1
1 3 5
Sample Output 2
No
If the first two pieces of information are correct, x3−x1=2 holds, which is contradictory to the last piece of information.
Sample Input 3
4 3
2 1 1
2 3 5
3 4 2
Sample Output 3
Yes
Sample Input 4
10 3
8 7 100
7 9 100
9 8 100
Sample Output 4
No
Sample Input 5
100 0
Sample Output 5
Yes 题意:给定有N个人,M条信息。每条信息:L,R,D,表示第R个人在第L个人的右边距离为D。求根据这M条信息判断安排是否成立。
题解:本来以为可以在线一条一条输入输入信息的同时判断是否合法,好像是不可以。答案说是构成图,然后DFS每一个节点。
#include<iostream>
#include<algorithm>
#include<cstring>
#include<vector>
#include<cstdio>
using namespace std;
const int maxn = 1e5 + ;
typedef long long ll;
vector<pair<int, int> > e[maxn];
ll dis[maxn];
bool vis[maxn];
int n, m,flag=; void dfs(int x)
{
vis[x] = ;
for (int i = ; i < e[x].size(); i++)
{
pair<int, int> cur=e[x][i];
if (vis[cur.first]) {
if (dis[cur.first] - dis[x] != cur.second) {
flag = ; break;
}
}
else {
dis[cur.first] = dis[x] + cur.second;
dfs(cur.first);
}
}
} int main()
{
cin >> n >> m;
memset(vis, , sizeof(vis));
for (int i = ; i < m; i++) {
int l, r, d;
cin >> l >> r >> d;
e[l].push_back({ r,d });
e[r].push_back({ l,-d });
}
flag = ;
for (int i = ; i <n; i++) {
if (!vis[i])
dfs(i);
if (flag) {
break;
}
}
if (flag) {
cout << "No" << endl;
}
else
cout << "Yes" << endl;
return ;
}
AtCoder Regular Contest 090 D - People on a Line的更多相关文章
- AtCoder Regular Contest 090
C - Candies 链接:https://arc090.contest.atcoder.jp/tasks/arc090_a 题意:从左上角走到右下角,只能向右和向下走,问能最多能拿多少糖果. 思路 ...
- AtCoder Regular Contest 090 F - Number of Digits
题目链接 Description For a positive integer \(n\), let us define \(f(n)\) as the number of digits in bas ...
- AtCoder Regular Contest 090 C D E F
C - Candies 题意 求左上角走到右下角最大的数字和. 思路 直接\(dp\) Code #include <bits/stdc++.h> #define maxn 110 usi ...
- AtCoder Regular Contest 061
AtCoder Regular Contest 061 C.Many Formulas 题意 给长度不超过\(10\)且由\(0\)到\(9\)数字组成的串S. 可以在两数字间放\(+\)号. 求所有 ...
- AtCoder Regular Contest 094 (ARC094) CDE题解
原文链接http://www.cnblogs.com/zhouzhendong/p/8735114.html $AtCoder\ Regular\ Contest\ 094(ARC094)\ CDE$ ...
- AtCoder Regular Contest 092
AtCoder Regular Contest 092 C - 2D Plane 2N Points 题意: 二维平面上给了\(2N\)个点,其中\(N\)个是\(A\)类点,\(N\)个是\(B\) ...
- AtCoder Regular Contest 093
AtCoder Regular Contest 093 C - Traveling Plan 题意: 给定n个点,求出删去i号点时,按顺序从起点到一号点走到n号点最后回到起点所走的路程是多少. \(n ...
- AtCoder Regular Contest 094
AtCoder Regular Contest 094 C - Same Integers 题意: 给定\(a,b,c\)三个数,可以进行两个操作:1.把一个数+2:2.把任意两个数+1.求最少需要几 ...
- AtCoder Regular Contest 095
AtCoder Regular Contest 095 C - Many Medians 题意: 给出n个数,求出去掉第i个数之后所有数的中位数,保证n是偶数. \(n\le 200000\) 分析: ...
随机推荐
- Django项目: 6.新闻详情页
一.功能需求分析 1.功能 新闻详情 加载评论功能 添加评论功能 二.新闻详情页 1.业务流程分析 业务流程: 判断前端传递新闻id是否为空,是否为整数,是否存在 2.接口设计 接口说明: 类目 说明 ...
- 1.关于Spring Cloud的一些基本知识
GA代表 general avaliable 通用可用版 也就是 正式发行版 PRE 代表预版本 就是还没有成熟 SNAPSHOT 快照版 这个版本可用 没有bug但是后期还会改进 选了这个spr ...
- int 13h,磁盘中断
直接磁盘服务(Direct Disk Service——INT 13H) 00H —磁盘系统复位 01H —读取磁盘系统状态 02H —读扇区 03H —写扇区 04H —检验扇区 05H —格式化 ...
- lumen使用CORS解决跨域问题
因为公司的业务是前后端分离,web前端和后端接口域名不同,所以存在跨域问题,开始使用的是jsonp解决,但是因为接口风格是rest的,还有delete.put等请求,jsonp就不够用了(涉及HTTP ...
- js 之 call 、 apply
在学习js过程中怎么也绕不过用到call.apply方法,感觉都差不多,现在看看他们的用法,区别 在 javascript 中,call 和 apply 都是为了改变某个函数运行时的上下文(conte ...
- finger 工具:用来查询用户信息,侧重用户家目录、登录SHELL等
finger 工具侧重于用户信息的查询:查询的内容包括用户名(也被称为登录名Login),家目录,用户真实的名字(Name)... ... 办公地址.办公电话:也包括登录终端.写状态.空闭时间等: 我 ...
- AntColony 磁力搜索引擎的核心
介绍 AntColony(Github)是findit磁力搜索引擎的核心.用来在DHT网络中,收集活跃资源的infohash,下载并解析资源的种子文件,存入数据库等.AntColony是若干功能的合集 ...
- vue前后端分离
axios前后端交互 安装 一定要安装到`项目目录下 cnpm install axios 配置 在main.js中配置 //配置axios import axios from 'axios' Vue ...
- Angungular.js 的过滤器&工具方法
字母大小写 数字 货币 截取字符串 截取数组 用JS操作 ----------------------------------------------------------------------- ...
- Uva116 Unidirectional TSP
https://odzkskevi.qnssl.com/292ca2c84ab5bd27a2a91d66827dd320?v=1508162936 https://vjudge.net/problem ...