Cod sursa(job #2678184)

Utilizator AlexTacuTacu Alexandru AlexTacu Data 28 noiembrie 2020 11:01:53
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 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];

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

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

void prg()
{
    fill(sol+1,sol+n+1,-1);
    q.push({s,0});
    bfs();
}

void afis()
{
    sol[s]=0;
    for(int i=1; i<=n; i++)
        out<<sol[i]<<' ';
}

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