Cod sursa(job #2678154)

Utilizator AlexTacuTacu Alexandru AlexTacu Data 28 noiembrie 2020 10:53:51
Problema BFS - Parcurgere in latime Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.23 kb
#include <bits/stdc++.h>

using namespace std;

ifstream in("bfs.in");
ofstream out("bfs.out");

queue < pair < int,int > > q;

vector <int> l[100005];

int n,m,s,sol[100005],viz[100005];

void citire()
{
    in>>n>>m>>s;
    for(; m--;)
    {
        int a,b;
        in>>a>>b;
        l[a].push_back(b);
    }
}

void bfs(int cer)
{
    if(cer==s)
    {
        q.pop();
        sol[cer]=0;
        return;
    }
    while(!q.empty())
    {
        int x=q.front().first;
        int y=q.front().second;
        q.pop();
        if(!viz[x])
        {
            viz[x]=1;
            for( vector <int> :: iterator i=l[x].begin(); i!=l[x].end(); i++)
            {
                if(*i==cer)
                {
                    sol[cer]=y+1;
                    return;
                }
                q.push({*i,y+1});
            }
        }
    }
}

void prg()
{
    fill(sol+1,sol+n+1,-1);
    for(int i=1; i<=n; i++)
    {
        fill(viz+1,viz+n+1,0);
        q.push({s,0});
        bfs(i);
    }
}

void afis()
{
    for(int i=1; i<=n; i++)
        out<<sol[i]<<' ';
}

int main()
{
    citire();
    prg();
    afis();
    in.close();
    out.close();
    return 0;
}