codevs1506 Messenger _codevs

Topic Description Description

A network of friends, if a knows B, then if a gets a message for the first time, it passes the message to B, and to everyone who knows it.

If a knows b,b not necessarily know a.

All the people from 1 to n numbers, give all "understanding" relationship, ask if I release a new message, then will pass a number of messages, this message back to I,1<=i<=n. Input description Input Description

The first line is N and M, representing the number of people and the number of cognitive relationships.

The next m line, two numbers a and b per line, represents a knowing B. 1<=a, B<=n. The cognitive relationship may be repeated, but a line of two numbers will not be the same.

Output Description Description

Altogether n rows, one character T or F per line. Line I if it is T, I send a new message back to I; if it is F, I send a new message that does not pass back to I.

Sample Input For example

4 6

1 2

2 3

4 1

3 1

1 3

2 3 Sample Output

T

T

T

F range and hint data Size & Hint

n<=1000

1<=a, B<=n

#include <iostream>
#include <memory.h>
#include <set>
using namespace std;
int n;
int m;
Set<int> node[1001];
int visited[1001];
int des;
BOOL Dfs (int i)
{
	if (visited[i] = 1&&i==des) return
		true;
	if (visited[i] = = 1) return
		false;
	Visited[i] = 1;
	For (Set<int>::iterator It=node[i].begin (), It!=node[i].end (); it++)
		if (Dfs (*it) ==true) return
			True ;
	return false;
}


int main ()
{
	cin >> n >> m;
	for (int i=0;i<m;i++)
	{
		int a, b;
		Cin >> a >> b;
		Node[a].insert (b);
	}
	for (int i=1;i<=n;i++)
	{
		memset (visited, 0, sizeof (visited));
		des = i;
		if (Dfs (i))
			cout << "T" <<endl;
		else
			cout << "F" << Endl;
	}
	return 0;
}