Cod sursa(job #1010538)

Utilizator miha88Popescu Mihaela miha88 Data 15 octombrie 2013 08:14:33
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.87 kb
#include <fstream>
#include <vector>
#include<queue>
#define nmax 1000005
using namespace std;
ifstream f("bfs.in");
ofstream g("bfs.out");
int n,m,s,d[nmax],x,y;
bool viz[nmax];
vector<int> a[nmax];
void citire()
{
	f>>n>>m>>s;
	for(int i=1;i<=m;i++)
		{
		   f>>x>>y;
		   a[x].push_back(y);
		}
}
void bfs (int x)
{
    viz[x]=1;
    queue<int>q;
    q.push(x);
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(int i=0;i<a[x].size();i++)
        {
            int p=a[x][i];
            if(!viz[p])
            {
                d[p]=d[x]+1;
                q.push(p);
                viz[p]=1;
            }
        }
    }
}
int main()
{
	citire();
	bfs(s);
    for(int i=1;i<=n;i++)
    {
        if(viz[i])
            g<<d[i];
        else
            g<<"-1";
        g<<" ";
    }
    return 0;
}