HDOJ題目3729 I'm Telling the Truth（二分圖）

I'm Telling the Truth

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1629 Accepted Submission(s): 805


Problem Description After this year’s college-entrance exam, the teacher did a survey in his class on students’ score. There are n students in the class. The students didn’t want to tell their teacher their exact score; they only told their teacher their rank in the province (in the form of intervals).

After asking all the students, the teacher found that some students didn’t tell the truth. For example, Student1 said he was between 5004th and 5005th, Student2 said he was between 5005th and 5006th, Student3 said he was between 5004th and 5006th, Student4 said he was between 5004th and 5006th, too. This situation is obviously impossible. So at least one told a lie. Because the teacher thinks most of his students are honest, he wants to know how many students told the truth at most.

Input There is an integer in the first line, represents the number of cases (at most 100 cases). In the first line of every case, an integer n (n <= 60) represents the number of students. In the next n lines of every case, there are 2 numbers in each line, X_i and Y_i (1 <= X_i <= Y_i <= 100000), means the i-th student’s rank is between X_i and Y_i, inclusive.


Output Output 2 lines for every case. Output a single number in the first line, which means the number of students who told the truth at most. In the second line, output the students who tell the truth, separated by a space. Please note that there are no spaces at the head or tail of each line. If there are more than one way, output the list with maximum lexicographic. (In the example above, 1 2 3;1 2 4;1 3 4;2 3 4 are all OK, and 2 3 4 with maximum lexicographic)
Sample Input

2
4
5004 5005
5005 5006
5004 5006
5004 5006
7
4 5
2 3
1 2
2 2
4 4
2 3
3 4

Sample Output

3
2 3 4
5
1 3 5 6 7

Source 2010 Asia Tianjin Regional Contest
Recommend zhouzeyong | We have carefully selected several similar problems for you: 3724 3722 3723 3725 3726 題目大意：每個人都說出自己所在的名次范圍，問最多多少個人說的是實話，並把說實話的人的號輸出出來，如果有多種情況滿足的話，就輸出最大的序列 ac代碼

#include
#include
#include
int head[100100],vis[100100],cnt,ans[100100],link[100100];
int cmp(const void *a,const void *b)
{
	return *(int *)a-*(int *)b;
}
struct s
{
	int u,v,next;
}edge[100010];
void add(int u,int v)
{
	edge[cnt].u=u;
	edge[cnt].v=v;
	edge[cnt].next=head[u];
	head[u]=cnt++;
}
int dfs(int u)
{
	int i;
	for(i=head[u];i!=-1;i=edge[i].next)
	{
		int v=edge[i].v;
		if(!vis[v])
		{
			vis[v]=1;
			if(link[v]==-1||dfs(link[v]))
			{
				link[v]=u;
				return 1;
			}
		}
	}
	return 0;
}
int main()
{
	int t;
	scanf(%d,&t);
	while(t--)
	{
		int n;
		scanf(%d,&n);
		int i,j;
		cnt=0;
		memset(head,-1,sizeof(head));
		memset(link,-1,sizeof(link));
		for(i=1;i<=n;i++)
		{
			int a,b;
			scanf(%d%d,&a,&b);
			for(j=a;j<=b;j++)
				add(i,j);
		}
		int top=0;
		for(i=n;i>0;i--)
		{
			memset(vis,0,sizeof(vis));
			if(dfs(i))
			{
				ans[top++]=i;
			}
		}
		printf(%d
,top);
		qsort(ans,top,sizeof(ans[0]),cmp);
		for(i=0;i