Codeforces Round #338 (Div. 2):(615A)
2016-01-26 10:50
295 查看
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".
Sample test(s)
Input
Output
Input
Output
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.
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".
Sample test(s)
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.
/* problem:cf-615A */
/* author: dang */
/* date: 2016-1-25 10:45 */
/* 题目大意:
1-m 数字全部出现,即YES ; 否则NO*/
#include <cstdio>
#include <cstring>
int main(){
int n, m, flag = 0;
int x, y, a[105]={0};
scanf("%d%d", &n, &m);
while(n--){
scanf("%d", &x);
while(x--){
scanf("%d", &y);
a[y]=1;
}
}
for(int i = 1; i <= m; i ++){
if(a[i]==0) flag = 1, i = m;
}
if(flag) printf("NO\n");
else printf("YES\n");
return 0;
}
相关文章推荐
- 使用C++实现JNI接口需要注意的事项
- 关于指针的一些事情
- c++ primer 第五版 笔记前言
- share_ptr的几个注意点
- Lua中调用C++函数示例
- Lua教程(一):在C++中嵌入Lua脚本
- Lua教程(二):C++和Lua相互传递数据示例
- 微软Word 2007数学插件 Microsoft Math 提供下载
- 关于C# Math 处理奇进偶不进的实现代码
- C++联合体转换成C#结构的实现方法
- C++高级程序员成长之路
- C++编写简单的打靶游戏
- C++ 自定义控件的移植问题
- C++变位词问题分析
- C/C++数据对齐详细解析
- C++基于栈实现铁轨问题
- C++中引用的使用总结
- 使用Lua来扩展C++程序的方法
- C++中调用Lua函数实例
- Lua和C++的通信流程代码实例