Cod sursa(job #2023732)

Utilizator Fanika123Tanasa Stefan Fanika123 Data 19 septembrie 2017 13:51:42
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
#include <bits/stdc++.h>
#define in "bfs.in"
#define out "bfs.out"
#define nmax 100003
using namespace std;
ifstream fin(in);
ofstream fout(out);

int n,m,s;
int d[nmax];
int viz[nmax];
vector <int> L[nmax];
queue <int> q;

void Citire()
{
    int i,x,y;

    fin >> n >> m >> s;
    d[s] = 0;
    for (i = 1; i <= m; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
    }
}

void BFS(int k)
{
    q.push(k);
    viz[k] = 1;
    d[k] = 0;

    while (!q.empty())
    {
        k = q.front();
        q.pop();
        for (auto i : L[k])
            if (viz[i] == 0 && i != s)
            {
                viz[i] = 1;
                d[i] = d[k] + 1;
                q.push(i);
            }
    }
}

void Rezolvare()
{
    int i;

    BFS(s);
    /// trebuie sa modific vectorul d
    /// pentru a marca nodurile la care nu pot ajunge diferite de s
    for (i = 1; i <= n; i++)
        if (d[i] != 0) fout << d[i] << " ";
        else
        {
            if (i != s) fout << "-1 ";
            else fout << "0 ";
        }
}

int main()
{
    Citire();
    Rezolvare();

    fin.close();
    fout.close();
    return 0;
}