Cod sursa(job #701840)

Utilizator soriynSorin Rita soriyn Data 1 martie 2012 18:04:53
Problema BFS - Parcurgere in latime Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 0.71 kb
#include<fstream>
#include<vector>
#include<queue>
#include<cstring>
#define maxn 100010

using namespace std;
ifstream in("bfs.in");
ofstream out("bfs.out");
vector<int>a[maxn];
queue<int>q;
int d[maxn],s,n,m;
bool viz[maxn];
void read()
{
	in>>n>>m>>s;
	int x,y;
	for(int i=1;i<=m;i++)
	{
		in>>x>>y;
		a[x].push_back(y);
	}
	memset(d,-1,sizeof(d));
	d[s]=0;
    q.push(s);
	viz[s]=1;
}

void bfs()
{
	while(!q.empty())
	{
		int nod=q.front();
		q.pop();
		viz[nod]=1;
		for(int i=0;i<a[nod].size();i++)
		{
			if(viz[a[nod][i]]==0)
		    {
			 d[a[nod][i]]=d[nod]+1;
			 q.push(a[nod][i]);
			}
		}
	}
}

int main()
{
	read();
	bfs();
	for(int i=1;i<=n;i++)
		out<<d[i]<<" ";
}