odeforces 615A. Bulbs
来源:互联网 发布:微信解封软件免费版 编辑:程序博客网 时间:2024/04/30 20:16
codeforces 615A. Bulbs
A. Bulbs
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Vasya wants to turn on Christmas lights consisting of m bulbs. Initially, all bulbs are turned off. There are n buttons, each of them is connected to some set of bulbs. Vasya can press any of these buttons. When the button is pressed, it turns on all the bulbs it’s connected to. Can Vasya light up all the bulbs?
If Vasya presses the button such that some bulbs connected to it are already turned on, they do not change their state, i.e. remain turned on.
Input
The first line of the input contains integers n and m (1 ≤ n, m ≤ 100) — the number of buttons and the number of bulbs respectively.
Each of the next n lines contains xi (0 ≤ xi ≤ m) — the number of bulbs that are turned on by the i-th button, and then xi numbers yij (1 ≤ yij ≤ m) — the numbers of these bulbs.
Output
If it’s possible to turn on all m bulbs print “YES”, otherwise print “NO”.
Examples
Input
3 4
2 1 4
3 1 3 1
1 2
Output
YES
Input
3 3
1 1
1 2
1 1
Output
NO
Note
In the first sample you can press each button once and turn on all the bulbs. In the 2 sample it is impossible to turn on the 3-rd lamp.
题目大意:n个开关控制m个灯泡,n个开关能否把所有灯泡打开。
#include<stdio.h>#include<stdbool.h>#include<string.h>bool vis[110];int main(){ int n,m; while(~scanf("%d %d",&n,&m)) { memset(vis,0,sizeof(vis)); int i,j; int x; int x1; ///将有开关控制的电灯标记为1 for(i=0;i<n;i++) { scanf("%d",&x); while(x--) { scanf("%d",&x1); vis[x1]=1; } } ///判断是否所有灯泡被标记 bool abc=1; for(j=1;j<=m;j++) { if(!vis[j]) { abc=0; break; } } printf(abc? "YES\n":"NO\n"); } return 0;}
- odeforces 615A. Bulbs
- CodeForces 615A Bulbs
- CodeForces 615A Bulbs
- CodeForces 615A Bulbs
- CodeForces 615A Bulbs
- 【CodeForces】[615A]Bulbs
- 【 CodeForces 615A 】 Bulbs
- 【CodeForces 615A】Bulbs
- Codeforces-615A-Bulbs
- 【 Codeforces 615A】A. Bulbs
- Codeforces 615A Bulbs 【水题】
- Codeforces 615A Bulbs 【水题】
- A. Bulbs
- CodeForces 615 A. Bulbs(水~)
- CodeForces 615A Bulbs (水。)
- 【CodeForces】615A - Bulbs(水)
- 【Codeforces】-615A-Bulbs(思维,模型:桶)
- Bulbs
- 在浏览器地址栏按回车、F5、Ctrl+F5刷新网页的区别
- S3C2440PWM 定时器
- android应用程序访问隐藏的api
- mysql中的判断是否有该条数据 如果有返回1 没有返回0
- tomcat缓存静态资源深入
- odeforces 615A. Bulbs
- 实现windows程序的数据绑定第五章
- [小插曲] vs2013 MFC 串口上位机设计的学习
- FileZilla远程管理无法登录
- Android Studio导入工程报错[Plugin with id 'com.android.application' not found]
- POI设置导出的EXCEL锁定指定的单元格
- XML
- 如何通过wifi调试手机上的android应用
- 贪心算法 迪杰斯特拉算法求最短路径