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Cod sursa(job #720425)
#include<fstream>
#include<queue>
#define MAXN 100010
#define inf 100000000
using namespace std;
ifstream in("bfs.in");
ofstream out("bfs.out");
struct graf
{
int nod;
graf *next;
};
graf *a[MAXN];
int n,s,m,d[MAXN];
void read()
{
in>>n>>m>>s;
int i,x,y;
for(i=1;i<=m;i++)
{
in>>x>>y;
graf *q=new graf;
q->nod=y;
q->next=a[x];
a[x]=q;
}
}
void bfs()
{
bool inqueue[MAXN];
for(int i=1;i<=n;i++)
{
d[i]=inf;
inqueue[i]=false;
}
queue<int> q;
q.push(s);
d[s]=0;
inqueue[s]=true;
while(!q.empty())
{
int min=q.front();
q.pop();
graf *g=a[min];
while(g)
{
if(inqueue[g->nod]==false)
{
inqueue[g->nod]=true;
d[g->nod]=d[min]+1;
q.push(g->nod);
}
g=g->next;
}
}
}
int main()
{
read();
bfs();
for(int i=1;i<=n;i++)
{
if(d[i]==inf)
out<<"-1"<<" ";
else
out<<d[i]<<" ";
}
return 0;
}